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Full text of "73 Magazine (August 1975)"

AUGUST 1975 
ONE DOLLAR 










Helical Antennas 

OPTIONAL THIRD GENERATION FLEXIBILITY 

SWR Computer 

BALANCED RECIPROCAL CAPABILITY 

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WB4VXP 


12 


K2PMA 


22 


K20AW 


25 


KICLL 


36 


W9KXJ 


42 


WB8D0T 


45 


WA5KPG 


58 


W1BNN 


62 


W7SHY/6 


69 


K4TW1 


70 


WB5IRY 


73 


VE3GSP 


80 


MICHIGAN RADIO DOCIOR 


92 


W2A00 


95 


SIAFF 


103 


K8BFH/1 


111 


W6GXN 


121 


VK30M 


141 


K7PVZ 


147 



The Oscar Zapper 

Identalert C 

Digital SWR Computer 

RF Feedback, The Experimenter's Curse 

Surveying the DVM Scene 

How About a Weather Satellite Monitor? 

The QRP Accu-Keyer 

Catenary Suspense 

Copper Rip-Off 

Better Results from those Sweep Tubes 

The Best Logic Yet 

How to Compact Multiband Dipoles 

Don't Feed the Bears! 

The Wonderful Mini-Chronometer 

An Accessory VFO — The Easy Way 

Modern Non-Morse Codes 

Build This Amazing Function Generator 

Charge that KP202 

So You Want Front-to-Back Ratio? 




#179 AUGUST 1975 







2 


Never Say Die 


137 


AMSAT 


3 


Hotline Headlines 


138 


New Products 


6 


Be My Guest 


140 


Super Circuits 


8 


Repeater Update 


140 


Correction 


10 


Letters 


144 


Hamburglar 


127 


FCC 


144 


Ham Help 


128 


Contests 


150 


Caveat Emptor 


133 


Ancient Aviator 


155 


Social Events 


134 


Looking West 


192 


Advertiser Index 


137 


Grrre?n 


192 


Propagation 



COVER: The notorious Oscar 
Zapper, by Alan Bridges 
WB4VXP. Article begins on page 
12. 

73 Magazine is published monthly by 73, Inc., Peterborough, New Hampshire 03458. Subsc rip lion rates are & for one 
year in North American and U.S. Zip Code areas overseas,. S9 per year e/se where. Three years, Sf6 and $17 overseas. 
Second class postage paid at Peterborough, New Hampshire 03458 and at additional ma i Zing offices. Phone: 
603-924-3873, MicrofUm edition of 73 avaiiabfe from University Microfifms, Ann Arbor Mi 48106. Magnetic tapes 
available from Science for the Blind, 332 Rock Hi if Rd., Bafa CynwydPA 19904, Entire contents copyright 1975 by 73 
inc. Peterborough NH 03458, 




/ 



mtf 



EDUOR/PUBLISHER 

Wayne Green W2NSD/1 

BUSINESS MANAGER 

Virginia Londner Green 

EDITORS 

Eric K. Albrecht K8BFH/1 

Alex BarvicksWB4RVH 
)ohn Burnett 

EDITORIAL ASSISTANT 
Susan G. Phil brick 

PRODUCTION MANAGER 

Lynn Panciera-Fraser 

ART DEPARTMENT 

Bob Drew 

Nancy Estfe 

Neal Kandel 

P&ri Mahoney 

Bob Sawyer 

PRINTER 

Bfff Mahoney 

PHOTOGRAPHY 

Bit! Heydolph 

TYPESETTING 

Barbara Latli 

ADVERTISING 

Bill Edwards WB6BED/1 
Nancy Cluff 

COMPTROLLER 

Knud E. M, Keller KV4GG/1 

MARKETING 

David H. Lodge 

CIRCULATION 

Barbara Block 

Susan Chandler 

Dorothy Gibson 

Judy Havey 

Cheryl Hurd 

Pearl La hey 

Marge McCarthy 

INVENTORY CONTROL 

Marshall Raymond 

PLANT MAINTENANCE 

Bill Barry 
Elaine Mercier 

ASSOCIATES 

Robert Baker WA I sex 

Schley Cox WB9LH0 

Tom OiBiase WB8KZD 

Terry FoH WB4 j Fl 

W. Sanger Green 

Dave I ngram K4TWJ 

Joe Kasser G3ZCZ 

Bill Pasternak WA6ITF 

JobnSchultzW2EEY 

Waller Scott K8DIZ 

Peter A. Stark K20AW 

Bill Turner WAPABI 

DRAFTING 

Bill Morel I o 

Lynn Malo 

T. M. Graham )r. W8FKW 




BYTEMAGAZIME 
The response to computer- type ar- 
ticles in 73 has been so enthusiastic 
that we here in Peterborough got 
carried away. I found myself enor- 
mously interested in the rapidly 
evolving microcomputer field and 
started subscribing to many of the 
small newsletters in the field. The 
more I read thp more enthusiastic 1 
got » . • and on May 25th we made a 
deal with the publisher of a small (400 
circulation) computer hobby 
magazine to take over as editor of a 
new publication which would start in 
August. . . BYTE, 

We figured we could print the first 
issues on our own small offset presses 
as the magazine gathered steam. We 
might run 5000 copies of a 24 page 
magazine for starters. Within a couple 
of days, with the telephone ringing 
constantly, we knew we had under- 
estimated the thing ... it would take 
a 10,000 run of 48 pages to meet the 
interest, A week later we were up to 
96 pages and a 35,000 press run, far 
beyond our small print shop facilities 
How come all the enthusiasm? Well, 
it appears that just about everyone 
who is in any way involved with 
computers has a very deep need to 
have one for himself. You can get a 
nice little computer working for under 
$500 and use it for a wide range of 
applications. You can hook in cassette 
recorders, television typewriters, and 
teletypewriters. All kinds of goodies 
are available surplus. The applications 
are myriad . . . some are using their 
systems to aim antennas for Oscar or 



BIG REWARD 

The big companies in amateur radio 
today were, for the most part, started 
by one or two amateurs , • , and many 
grew very rapidly as a result of the 
low ad ratBS in 73 and the wide 
circulation among active (buying) 
hams. We'll give you 10% of the first 
ad run by a new company if you let us 
know about them and they advertise 
first in 73, Do yourself and the new 
firm a big favor — drop a note to 73 
Advertising, Peterborough NH 03458. 



EDITORIAL BY WAYNE GREEN 



moonbounce, some for keeping track 
of their music or book libraries, some 
to index ham articles, some to auto* 
matically print weather satellite 
pictures, some to automate RTTY 
stations, some to run their home 
security systems, and almost all to 
play a wide range of games. 

Calls come in daily with more 
uses . * * one chap has a program to 
look for key words in any text and set 
your printer going when matter comes 
up of interest. Suppose you tune in 
the RTTY broadcasts of the Con- 
gressionai Record every day and scan 
it for the words "amateur radio/' 
Others are working out ways to make 
use of the one minute phone rates for 
a maximum exchange of information, 
computer to computer. Remember 
that there is no charge if your com- 
puter is called and tells the calling 
computer that it has nothing for 
it . . . or if the exchange is under a 
second or two. Many of the com- 
merciaf computer systems use this 
aspect of the phone system . . . polling 
dozens or even hundreds of computers 
through the night and only inter- 
connecting {with a phone charge) 
where there is traffic to be passed. 

Most of the top writers in the field 
have leaped to help get BYTE going in 
good style and articles are pouring 
in . - Jots of information on the pre- 
sently available microcomputers such 
as the Altair 8800, the Sceibi 8B, RGS 
008 A, etc. BYTE will cover inter- 
connecting to these units, peripherals, 
interfaces, the circuits and con- 
struction plans for buifdtng your own 
CPUs, news of alt user clubs, news of 
programs available and how to get 
them, news of all specialized pub* 
lications, explanations of all computer 
terms and how the various computer 
programming systems work. 

In no time at all you'll be throwing 
around computer buzz words such as 
loader, compiler, assembler, basic, 
Dibol, Cobol, machine language, byte, 
bit, word, flag, and so forth. 

Computers will be adding a whole 
new dimension to amateur radio . . , 

you wait and see. Right now you 
have the choice of getting in at the 



7_lMAnA7IWP 



beginning of a fantastic new hobby or 
waiting and trying to catch up later 
on. First issues of BYTE will be as 
rare as early issues of 73 . . , you'll 

BYTE will be Si, 50 per copy, 
suba;ription $12 per year, and a 
Charter Subscription is only $10, 
BYTE, Peterborough NH 03458. 

MORE BAD NEWS FOR OTs 

The 'W clan are in for another 
massive trauma which may regress 
them even further into the old spark 
days. After a good solid ten years of 
having to read about transistors and 
five years of rapid strides in IC tech- 
nology, many old tinners are still 
shaking their heads and waiting for 
the return of the tube. Fellows, you 
might as well start cracking the books 
because you can't even pass a ham 
exam anymore without solid state 
savvy. 

And what is coming up . . . rap- 
idly • . . is a whole new technology 
that we are all going to have to 
accommodate, whether we like it or 
not. It's them ICs what done it to us. 
When I was a youngster I used to 
wonder why they didn't make micrch 
circuits . . . now I see why , , < the 
whole thing has gotten completely out 
of hand and is taking over ... they 
never should have started. Massive 
monolithic integration . . * micro- 
putianism gone berserk. 

You've undoubtedly seen the RGS 
ads for the 8008 microcomputer 
kit.,, the MITS Altair 8800 micro- 
computer kit . . , the Southwest Tech- 
nical keyboard visual display 
kit . . . so you probably sense on some 
level that computers are beginning to 
creep into your world. What you may 
not realize ts that you are going to 
have to adjust to them and learn to 
talk the language . . , and think it. 

If you are shifting around uncom- 
fortably, thinking that well, shucks, 
sure . . - you can bone up on digital 
stuff and get it straight about those 
damned nand and eitheror gates, you 
are in for a ghastly awakening. They 
are building thousands of transistors 
into those ICs these days and what has 
developed is a whole new approach to 
dealing with the situation. It's called 
programming ... or software, if you 
prefer the computerese buzzword. 
This is the system by v^ich you can 
get these incredibly complex little 
biack boxes with those funny centi- 
pede legs to do something useful for 

us. 

Software. This can be the throwing 
of a bunch of switches to feed the 



instructions to the circuits — or it 
can be typing on a Teletype key- 
board ... or data from a tape cas- 
sette ... or punched tape * . • etc 
There are a raft of "languages" used 
to put the instructions into com- 
puters . . . basic, machine, fortrans, 
cobalt, diabolic, assembly, and 
others . . . many others. You are going 
to be learning some of these lan- 
guages. The chances are that you will 
eventually get familiar enough with 
them to actually understand what you 
are talking abouL 

Is it worth all the work? No ques 
tion about it ... if you are one of 
those who is the first in his block to 
get new things you'll be eating up the 
articles on software systems as they 
come out ... if you are the guy who 
never gets the word you'll be missing 
out on more fun than you can 
imagine. The new microprocessor 
chips are opening up a fantastic (and 
complicated) world for us. 

The prices on this stuff will be 
much like those of hand calculators 
and digital watches . . . relatively high 
at first and then dropping rapidly as 
more and more people find out where 
the action is and volume picks up. I 
remember all the resistance I ran into 
in 1948 when I wanted to buy a 
television set . . . they were very ex- 
pensive . . . about $750 for a 10" 
black and white set by today's 
dollarette standards , , . turned out to 
be one of the best investments I could 
have made . . , years of enter tain- 
ment,.,and I got to see all those 
fantastic early programs you missed. I 
bought one of the first transistor 
radios too ... a Regency . . . expen- 
sive . , . and I never regretted it. You 
can miss a lot of fun waiting for that 
price to drop. 

We'll try to do the best we can on 
getting articles for you . , . if you have 
an article of value lurking in the back 
of your mind, get busy and write it 

"^" WANTED 

We're getting up to here in old files 
and would like to start microfilming 
the stuff. On the odd chance that 
some reader has a microfilm or micro- 
fiche camera, film processor and 
reader system available . . . hopefully 
at a bargain ... this notice is given. 

We're needing some cassette dup- 
licators too, if there are any of those 
flying around that are not badly 
needed* 

Another need: IBM Selectric U 
typewriters- ,, used. Also we could 
use a couple of Teletypes with forms 
feeders, ^ ^ ^ W2NSD/1 



HOTLINE 
HEADLINES 

Pacific Telephone brings national 
spotlight to 73 Magazine with suit 

over circuits in June issue. Other ham 
publishers furious over PR coup. 
Citing the circuits in the Inside Ma 
Bell series in 73, PTT brought suit for 
5100,000. Dealers immediately ran 
out of counter copies of this issue and 
subscriptions were up substantially. 
Emergency Beacon Canceled. Alt 
further advertising in 73 Magazine has 
been canceled by the publisher until 
some problems with meeting spei^ 
and customer relations have been re- 
solved. 
QST board votes unanimously to 

increase size of the magazine to about 
that of Radio Electronics — members 
not consulted in this major decision — 
no benefits to members likely. 
Increased size will make for many 
problems, few economies. Other ham 
magazines will certainly be forced to 
follow QST in size change. This 
appears to be change for the sake of 
change. 
RFI bill introduced in congress _ 

HR7052 will regulate susceptibility of 
home entertainment devices to radio 
interference. Get your congressmen 
to push this one. 

Saroc Hawaii convention dis- 
appointing. Commercial "convention" 
for profit run by defrocked ham 
attracts few despite allure of Hawaii 
and strong backing of one ham maga- 
zine. 
Rochester hamfest a winner this year. 

Attendance estimated at 3500 — 
money was a bit tight according to 
exhibitors - possibly due to cash 
draina^ at Dayton a few weeks 

earlier. 

California fights Bell - prohibits steep 

rates for insignificant bits of hardware 

such as answering machine and phone 

patch couplers. 

ARRL breaks S2 million in 1974. 

Despite reported lo^ for the year (a 

small one), cash and stocks are now 

totalling nearly a million dollars, 

building up steadily. When is a loss 

not a toss, IRS? 

Wichita Amateur Radio Club has the 

most outstanding comment filed on 

docket 20282 — reprinted in entirety 

in Hotline =31. Goes right to the 

I heart of the matter and lays it on the 
tine. 

SSTV contest winner: WB4ECE. 
Runners up - WA1NXR, W9NTP, 
WB9LVI and G3IAD, 






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73 MAGAZINE 



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AUGUST 1975 



5 



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BE MY GUEST 

VLsiling lietvs from around the globe. 



HOW TO GENERATE 



YOUR OWN INTERFERENCE 



In the pest year, WR2ABU has been 

plagued with incidents of malicious 
interference, illegal stations with 
obscene "traffic" and other harass- 
ments. Dick's phone has been ringing 
off the wall with members demanding 
that "The Club" do something about 
it. Well, the Club did. An unnamed 
Committee was established wfth the 
purpose of tracking down the offen- 
ders. It was unnamed because we were 
well advised to keep the Committee's 
activities, methods and identities a 
secret. 

The Committee's investigations pro- 
duced results in an amazingly short 
time. In several instances surveillance 
cars monitored illegal transmissions 
from right next door to the offending 
source. Names and addre^es were 
obtained. Every new call on the air 
W3S investigated via FCC files. 



It is not the purpose of this article 

to talk about the Committee, 
however. 

Most of the offenders turned out to 
be part of a "hate ham radio group" 
consisting of a group of Citizen's band 
operators. Although the evidence was 
overwhelming, I couldn't help but 
wonder why they would hate us. What 
do they have against amateurs? Since 
their interests so closely parallel ours 
does it not follow that every CB 
operator is an aspiring amateur opera- 
tor. 

For me the answer was not long in 
coming. All I had to do was listen to 
the repeater for a couple of days. 
Whenever something bad comes up 
the speaker blames it on "those 
CBers", When something derogatory 
about an operator is called for (?) he 
is called a CBer. CBers are ridiculed, 
scorned, taunted and verbally abused 



Admq PnjBkAAt&Koi 



Some of ttie largest problems the 
SCR A elected officers and appointed 
officials have had to contend with 
over the past three years have come 
from within the ranks of our own 
membership. The systems whose idea 
of support is to agree with you only as 
long as you agree with them; those 
systems who wave their flag of SCR A 
membership as though it gave them 
divine right to do as they please; those 
systems who bend and twist every 
word in an effort to subvert the very 
job the SCR A was created to do: 
those systems who scream mter- 
ference if, by pointing their yagis at 
exactly 127^37', a new co-channel 
user breaks their squelch; those 
systems who cry foul if the SCR A 
dares to propose an adjacent-channel 
system within 800 miles of them; 
those systems who hang up on you 



when you call to tell them their 

"local" machine is devastating 25,000 

square miles. Until you've actually 

been there, you wouldn't believe it! If 
you ask them about it, they tell you 

to go pick on somebody else, after all, 
as members of the SCRA, we should 
be helping and supporting them, not 
harassing them, etc, etc. Maybe ft is 
tinrre the SCR A reassessed its valu^ 
since some of its members appear to 
have lost theirs. To be supported, you 
must support; to be helped, you must 
help; to be an Amateur, you must act 
professional. Should this trend con- 
tinue, it, like a cancer, will doom the 
SCR A to a slow and painful death. If 
it does, I, for one, will grieve. 

Charles R, Flanagan W60LD 

Chairman, Southern 

California Repeater 

Association 



in every convet^atton they are dis- 
cussed. 

In short, gentlemen, WE ASKED 
FOR IT! I'm not sympathetic in any 
way with those who would for any 
reason deliberately and maliciously 
cause interference to communications, 
but I believe it is time for us to 
administer a cure. 

First, our attitude towards CB must 
change. Sure, the 11 meter operations 
leave a lot to be desired. Yes, there are 
many poorly qualified CB operators 
and much of the worst we think about 
CBers is true of some of thenx But 
how do you feel when someone makes 
a derisive remark about ham radio, 
citing the actions of a ham that you 
don't like any better than he does? 
What we are doing is blaming ALL 
CBers for their ills. Aren't they 
people, each with an individual per- 
sonality? Is it fair to generalize and 
say that anyone who holds a CB 
license is all bad? If so, we better start 
weeding out those in our own ranks 
because many hams also hold CB 
licenses. 

And why not? CB has a legitimate 
intent, just as amateur radio does. If 
all radio services were to be dis- 
continued due to abuse all you would 
hear one radio is static. 

Stop for a moment and consider 
the relationship between ham radio 
and CB, Before the Citizen's Band 
service was established, a person with 
an interest in radio had two choices: 
listen only, becoming an SWL; or 
study and work toward an amateur 
license. SWLs were never the object of 
ridicule or slander by hams. They 
were considered potential hams and 
were treated with friendliness and 
encouragement. Classes were held by 
ham clubs to help them obtain 
licenses. This process continues today, 
but haven't you noticed that there are 
fewer SWLs lately? Has it escaped 
your notice that the average age of 
members of ham clubs is increasing? 



7.^ ]UtAnA71MC 



Look around at your favorite ham 
club the next meeting you attend 
COUNT! How many young fellows 
atB there? 

What IS happening is that there is a 
third choice available to the young 
SWL today. The path to a CB license 
Is easy and tempting. Granted, many 
of the people that take It might not 
make good hams, but what of those 
who would? I'll bet most of the 
people who would have otherwise 
become good amateur operators are 
now going into CB. We can't expect to 
turn the tide from CB because the 
easier path will always be followed, 
but there are things we should be 
doing and most importantly there are 
things we SHOULDNT BE doingf 

What we should do is to consider 
CB as the source of new amateur 
operators. The first stage of filtering 
from the general public has already 
taken place — all we have to do is to 
provide encouragement, incentive and 
cooperation. Those having sufficient 
interest to make it will then become 
amateurs and both will be gainers. We 
should contact legitimate CB groups 
and establish understanding with 
them. We should do what we can to 
make amateur radio an attainable goal 
for those willing to work for it. 
Finally, we should help make them 
WANT to become qualified amateurs. 

What we should NOT do is to use 
our licenses {and repeaters) as the 
means for public denunciation of 
CBers. If they weren't interested in 
amateur radio, why would they be 
listening in on the repeater? They 
should certainly not hear themselves 
insulted — that only alienates them 
and causes them to hate amateurs. 

Unless we start to face reality soon 
things will get a lot worse before they 
get better. Even the best of Com- 
mittees (such as ours) won't be able to 
do much good. 

Don't make nasty or unfair remarks 
about CBers on the air. Don't let 
others doing it stand unchallenged. 
The only way listening CBers can 
defend themselves is by kerchunking 
or transmitting interference. If you 
say it for them they won'^t have to* If 
the subject compels you to make 
negative statements, change it! 

Don't say CBers when you mean 
LID. If you like to make enemies, the 
repeater is the place to do it whole- 
sale. 

Gilbert BoelkeW2EUP 

Reprinted from The Link, Bulletin of 
the Buffalo Amateur Radio Repeater 
j^n. Inc., May 1975, 



reading everything 



The local QRPer, who was worrying 
about the DXCC fees a week back, 
came up the hill again last week, 

"You know something/' this 
QRPer said, "I understand that the 
ARRL has been losing money and 
that they are going to have to dig it 
out of somewhere . . , like the DXCC 
for instance. Did you know that?" We 
had read this over the years, so we 
nodded our head, thus preserving our 
erudite facade. The QRPer smiled at 
our reply and we should then have 
been a bit suspicious * • , just a bit. 

"You know something/' he con- 
tined, "I checked back to 1964 and 
would you believe that every year 
since 1964 the ARRL has shown an 

operating loss eleven straight years 

of deficits?" We nodded again to this, 
but the QRPer ranied on without 
waiting for our reply. "And that the 
total of these eleven years of deficits 
runs to about 5470,000?'' And again 
we nodded, for these are parlous times 
and many must bear a heavy burden. 
But the QRPer was smiling again and 
for sure by then we should have been 
wary. 

"Do you know/' the QRPer asked, 
"that last year they reported an 
operating loss of $137,547 but they 
showed an asset increase of 



$216,546?" Son of a Gun — we were 
on our feet at this for something was 
not adding up* "How do you figure 
that?" we roared, for we were feeling 
trapped again. "How do you figure 
they had the assets go up so much 
when they lost over a hurwdred thou- 
sand?" 

The QRPer shrugged. "Don't ask 
me," he said. "All I know is what I 
read in the Annual Reports. And since 
1964, when the operating loss was 
over $470,000, the assets increased 
over a half million. That's all I know." 
He was saying this, but that 
beady-eyed smile was just a bit 
brighter. 

We thought this over for a bit "I 
hear what you're saying/' we said, 
"but what does all of this mean?" 

The QRPer was quick to reply. "It 
means that we DXers are fortunate to 
have someone to watch out for our 
interests," he said, and away he went 
down the hilL 

And vexed and bewildered, we dug 
out our own Annual ARRL reports. 
All we can say is that QRPer sure does 
read everything. 

Reprinted from West Coast DX 
Bulletin, 7a™? 2, 1975. 



If amateur radio operators 

throughout the nation would follow 
the example of those in little Union 
City, Tenn. {population 13,500), they 
probably would be petitioning the 
FCC for new frequencies, rather than 
fearing the toss of some they now 
have. 

During the past few months, mainly 
through the ef forte of Willie Pope 
K4VDQ, radio classes have been 
organized and 11 new Novices 
licensed, while others have upgraded 
to Advanced. 

The story actually began last winter 
when Mr- Pope returned to the local 
radio station in Union City after 
having worked for some years in 
Orlando, Fla. 



While there were a number of hams 
in Union City, most were going their 
own merry way and little was being 
done to teach the art to the younger 
set. Something had to be done to 
revive the interest among the youth in 
amateur radio and Willie proved to be 
the catalyst. 

He rounded up Glen Leggett 
K4GMQ and Bill Porter WA4PRA, 
and plans were hastily worked out to 
conduct a Novice instruction class and 
to organize the Reelfoot Amateur 
Radio Club. 

Stories were run in the Union City 
newspaper and aired on the radio 
station, and between 17 and 18 

Contfnued on page 143 



Taking Action 



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MISSISSIPPI 

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PRECES A SPECirtCATI&NS SUBJECT TO CKANCC WltHfiUt NOTICE. 
*HAILOA;dER PillCE&i F.O,B. FACTOiTY. 



AM-31 4 



I 



AUGUST 1975 



ou goons 

1 



don't ever 



r 




I insist that you print 



n 

ev 



SWEATING IT OUT 



Mr. Spenser Whipple, Jr. 
c/o 73 Magazine 
Peterborough NH 03458 

Dear Mr Whipple, 

I have just unglued my eyeballs 
from your June article on couplers for 
the third time! 

f am sweating it out until you 
publish your next article where you 
prornised to take up the discussion of 
teEephone couplers for answering 
machines. 

I just inquired of the California 
Public Utilities Commission about 
their Interim Order Number 138, This 
opens up the fietd of customer 
designed telephone couplers, if they 
are approved by a Registered Pro- 
fessional Engineer (EE}. 

Only two, one fellow out in Chats- 
worth, California, and myself, sent in 
an ordinary inquiry letter, and Bang! 
They put both of us on their approved 
engineer list! Yeah, just for opening 
our big mouths and asking for infor- 
mation. 

So, I am scrambling around trying 
to re-build my telephone engineering 
reference library, I di^osed of it nine 
years ago when I tried to retire, hi! 
So, all circuits and descriptions of 
approved types of telephone couplers 
for telephone answered machines are 
most welcome* 

Again, i am looking forward to 
your next article. 

E. Kenneth Taylor W6WT 

Communications Consultant 

8528 West Harg is St 

Los Angeles CA 90034 



THE GOOD . , . 



With all the bad deals consumers 
seem to get hit with these days, 
there's still hope for us. 

I saw an ad in 73 by S. D. Sales, 
Dallas, Texas: Digital Clock Kit, $9.95 
ppd All parts less transformer and 
case. Almost too good to be true. I've 



wanted one of these things for years, 
but sixty bucks always seemed such a 
waste for a clock. This offer was more 
in line with my price range, 

i sent the $9.95 and three days 
later a small box from S. D, Sales 
arrived. Talk about fast service. But 
when I opened the little box, alas, the 
chip and socket were missing. I 
immediately fired off a letter ex- 
pressing my displeasure and asking for 
a free circuit board, if they had one, 
to dampen my ire. Once again, three 
days later, another little box. Inside: 
clock chip, socket, double size circuit 
board layout, Vi dozen free MV-50 
LEDs — and an apology- 

In two days time, I laid out a 
board, reduced it 50%, and printed, 
etched and drilled iL By 8:00 pm 
that night I had it going, and played 
with it for several minutes trying to 
get it on the second with CHV. 

Now let me tell you I'm impresed 
to no end. The only problem is that 
the XYL doesn't understand GMT, 
and now I guess I'll have to order 
another one for EDT, 

Anyway, all 1 need now is a box to 
put it in, and it will make tracking the 
Oscars and working satellites a lot 
easier. 

I've got to hand it to this company 
— a real bargain, and once again 73 
scores with me. 

Bill RicharzWAWAF 
Charlotte WC 

That digital clock kit, $9.95, from 
S, D, Sales, Dallas, is great- Several 
already in operation here at State 
Tech plus one on my operating desk 
at home. 

LeRoy Dean C lough W5GQV 

Waco TX 

As you know, some "bargains" are 
not anything of the kind, but the 
Digital Clock Kit advertised in the 
June issue by S. D. Sales Co. is a 
genuine jewel. The soldering requires a 
magnifying glass, but the results are 
worth the trouble. A lot of thought 
went into the kit. I've ordered more* 

You may or may not be interested 
to know that my "Me Friend" piece 
in the June issue brought some un- 



expected mail - W6DEF, K6AJG, 

K3CHP and a half dozen or so others 
which were inadvertently filed in the 
1 RS basket and lost before I cou Id 
answer them. Sorry about that — I'm 
scrupulous about answering nice 
letters. Anyway, it surprised me, 

Kan Cole W7IDF 
Vashon WA 

A longtime contributor to 73, W7IDF 
swears up and down that "We Friend** 
wBs his only connection with our June 
issue. Our sources in the Northwest^ 
though, report that Ken has been 
sighted at several watering spots in the 
company of none other than ''Dear 
Gabby" (June, page J 72). — Ed, 



THE BAD . . . 

I am also a victim of Trigger Elec- 
tronics, 7361 North Ave,, River 
Forest IL 60305. I mailed an order on 
Jan. 4, 1975, and the check was 
cashed Jan. 13. Both sides of the 
check show the stamp, "Trigger Elec- 
tronics — Trigger W9IVJ". According 
to the Callbook, W91VJ is "Irael 
Treger*'. whose address is the same as 
that of Trigger Electronics. 

I've mailed him a copy of the 
check, and I'm waiting a few weeks 
for the results before I give another 
copy to the "postal inspectors". If 
enough folks can put "postal inspec- 
tor on the ball", perhaps it could then 
start rolling in the right direction. To 
me, this appears like using the "mail 
to defraud" - and it's time we went 
after him. 

Scotty Bottom 
Worcester MA 



AND THE UGLY 



This is my first letter to a ham 
magazine. I am writing in to protest 
the way 1 was treated while working 
for my Novice license. I do, however, 
want to say that I have met a few 
amateurs who did help me. But for 
the most part I w^ treated as if I did 
not exist I did join an amateur radio 
club, only to find the club was of 
little or no help. When I would ask 
one of them to help me with code 
they would say they had no time- 
When I would ask one of them to help 
me with theory the answer was there 
was nothing they could do to help me. 
Welt, the fact remains that I am one of 
those people who, finding a wall in 
front of him, will fight to overcome it, 
and I did — I have my Novice license. 



TO 



73 MAGAZINE 



And the thing that kept me going was 
the thought of being able to walk in 
and tell them that even without their 
help I got my license. Most people are 
not like that — if they hit a wall like 
that they give up. Proof of that is 
shown by the fact that f brought 3 
friends who are very interested in 
radio to the club and only one of 
them stayed, I think these hams who 
think themselves so great had better 
wake up to the fact that they are 
going to fose to CB operation many 
would-be hams because of their way 
of treating newcomers. 

Wayne S. Gateman WN1UXS 
Newton Centre MA 



nRlSTFtfL OF DOLLARS 

After a little bit of experience with 
the quartz digital watch I won in your 
bumper sticker contest at the Dayton 
Hamvention, it is hard to recall how I 
got along without it. Resetting my 
previous watch several times a week 
had become a way of life for me. Now 
a weekly hack with CHU or WWV 
keeps me within a second anytime- 
Needless to say, 1 am quite happy 
with my new CHRONEX. 

Funny thing, Wayne, many people 
have remarked about how lucky I was 
and how they never win anything. I 
always ask if they were aware of the 
contest — those who subscribe to 
HOTLINE invariably were. Then I ask 
if they got a bumper sticker and put it 
on their car. So far, not one has 
answered yes. How can they win if 
they don't try? For me it meant a 5Qi 
LED watch and a free bumper sticker. 

Thanks very much for the contest. I 
hope you have more. There are lots of 
other things I could use . , . 

Dixon Swrtzer W8KRV 
Bel I brook OH 



FAT ALBERT A VD THE M OB 

Have read your magazine ever since 
I saw a copy in the PX when I was in 
Germany in 1962. Outstanding!!! 
Especially the editorials about the 
Infernal Revenue Service. Have be€n 
in ham radio since 1956 and started 
out in Albuquerque. Am now in a 
town that is in the fringe area of 5 
repeaters (60-140 miles away) and has 
only 3 active VHFersI Your readers' 
comments on overcrowded channel 
conditions on 2m are hard to relate to 
when the only active channel is 94t 

I would like to suggest a new ally 
(If we'll appeal to them) in the hams' 



fight to keep CB off 220: namely, the 
military and NASA. Out vwst of us 
here in New Mexico is White Sands 
Missile Range, and Holloman Air 
Force Base, both top secret installa- 
tions. They are so important they 
have an FCC frequency coordinator, 
out in the boondocks! Any ham who 
calls out on 220 wilt be told to move 
immediately! No ifs, ands or buts. 
Those frequencies are used extensively 
in this area - "get off, period.", etc. 
Now, I ask you, will the unruly mob 
now squatting on 27 MHz cooperate, 
or even attempt to cooperate with this 
lawful order (shared with government 
radioposjtioning service, which has 
priority)? Lord NO, they won'tli! 
Therefore, my suggestion is: write to 
the Army, which runs White Sands 
and other similar install at tons, and 
write to NASA. Tell them of the 
devastating consequences to their vital 
efforts if CB is allowed on 220, and 
ask their help* Remind them that 
when they ask hams to QRT it is 
done, Teli them that the frequencies 
they occasionally need so much will 
be complete and utter chaos if Fat 
Albert and the mob come up on 220. 
Our fight may be ended much quicker 

this way. 

Bob Isselhard K5tNW 
2100 North Cielo 
Hobbs NM 88240 



STLRRMU 



We thought that you would be 
interested to know that we have de- 
veloped what could set a precedent in 
two meter communications con- 
testing. We call it "'Spontaneous, Time 
Limited, Rapid Relay, Message 
Handling", ft is, in essence, a message 
issued suddenly, without any previous 
announcement, on a local repeater. 
Included in the message is the starting 
time, ending time, and encouragement 
to send the message via two meter 
repeaters as quickly and accurately as 
possible. At the end of the message is 
the address of the originating station 
(or club) requesting a copy of the 
message, and the location of th© last 
repeater that it went through. 

Following is a copy of a message 
that we sent last April 26, and the 
response that we received. 

Original 
Message No. 1: Originated by 
STARRS, WR2ABL Date: 4/26/75. 
Time: 9:45 am. Text: Please relay this 
message through available two meter 
FM repeaters as rapidly and accurately 
as possible until 12:45 pm today. At 



that time, it is requested that the last 
station receiving this message pfease 
send a copy to STARRS, P,0. Box 
301, Corning, New York 14830. 
Thanks. 

Response 
No. 1A: From WR2ADL/Check 45 / 
Daytime Group 0953/ 4/26/75/// 
Text Please relay this message 
through all available FM repeaters as 
rapidly and accurately as possible up 
hill 12:45. It is requested at this time 
the last station receiving the message 
be ^nt to S.T.A.R^S., P.O. Box 301, 
Corning, New York 14830. Thanks, 

This response was sent in by Guy 
R. Williams at Corry, Pennsylvania. 
The message traversed several re- 
peaters located at Eimira, Owego, 
Binghamton, Ithaca, Auburn, Rome, 
and ~ we theorize — Syracuse, 
Rochester, Buffalo, New York and 
Corry, Pennsylvania. 

We believe that this type of two 
meter message handling has not really 
been tried before (at least we have not 
heard of such) and hope that it might 
catch on as a method of contesting, 
and also as a technique of excercising 
the potentially great capabilities of 
two meter repeaters. 

Bryant Hozempa WB2LVW 

Editor — Kerchunk 

Director - S.T.A.R,R-S- 

Coming NY 

TIU: FLIPPER SHOW 

That slide synchronizer in the June 
issue, page 155, is a good start for a 

slide show. However, depending on 
the money and time you want to put 
into your system, you can do some 
incredible things with slides synchro- 
nized with sound- 

If you have two projectors of 
roughly simitar make, that have con- 
trol of the lamp circuits and change 
circuits, you can keep the screen from 
going dark with a gadget called a 
Flipper. Simply, it switches back and 
forth the lamps, immediately after the 
"flip" command is given from a push- 
button control Of tape synchronizer — 
and then, the projector that is "dark" 
changes slides. This allows you to 
switch images on the screen almost 
instantly, and in time with music, and 
can create some spectacular effects. 
Those of you with digital knowledge 
can see how some TTL and a couple 
of relays can do the job for less than 
twenty bucks. You will gulp when 
you hear that the cost of a com- 
mercial Flipper is $120, 

Cortiinued on page 130 



AUGUST 1975 



11 



Alan L. Bridges WB4 VXP 
2754 Pine Hill Dr. NW 
Kennesaw GA 30144 



The Oscar Zapper 



Part Two 




The pjexigiass supports of the 70 cm helix 
with the helix conductor mounted on the 
supports and with the plexiglass rods per- 
manently bonded to the strips. Note how 
close the supports are, and the spacing of the 
supports every 90" along the turns of the 
helix. 



Last month, I discussed the basic charac- 
teristics and the general design para- 
meters that one must be familiar with in 
talking about helices. This part of the article 
is devoted to the actual construction of the 
antennas and the installation of the array at 
my QTH. Basically, the antenna array is four 
helices mounted on a thirty foot tower with 
an azimuth-elevation drive. The original 
installation was completed last summer, but 
this spring I have taken the array down to 
modify the az-el drive; this will be discussed 
later on in the article. 

Design, Construction And Installation 

The helices that make up the array 
consist of a pair of antennas, of opposite 
sense, for both 2 meters and 70 centimeters. 
The basic design parameters were followed 
fairly closely. A circumference of 1 .OOX was 
chosen, although after having constructed 
the antennas the measured or actual circum- 
ference was nearly 1.05X, an acceptable 
value. The design or center frequency for the 
helices was 146 MHz and 432 MHz respec- 
tively for the 2 m and 70 cm bands. The 
dimensions corresponding to these fre- 
quencies were calculated according to the 
optimum design parameters, and for C\ = 
1 .OCA the spacing Sx and the diameter Dx 
are summarized below. 



12 



73 MAGAZINE 




liii 



The 2 meter heliK under construction. The ground plane is 6 feet in diarneter and here the 
helix has 8 turns instead of the 6 turi^ that we end up with. 

For the 2 meter hences: 

X= 80.9 in -2,05 m 

CX = 1 .OOA (Actual value - 1 .OSX) 

SX = 0.22X - 1 7.8 in (Value of ~ 1 8 is 

used) 

DX = 032X=25.9in 
For the 70 cm helices: 

X' 273 in = 69,4 cm 

CX = 1 .OOX (Actual value -^ 1 .05X) 

SX-0.22X = 6.0In 

DX=032X-8,8in 

For the 2 meter helices the spacing and 
diameter are roughly 18 and 26 inches, 
whereas on the 70 cm helices the spacing 
and diameter are roughly 6 and 9 inches, 
respectively- The axial length, nSX, plus the 
distance from the ground plane to the first 
turn of the helix, is the total length of the 
helix, and for the 2 m and 70 m helices this 
is approximately 9,75 feet and 52 inches, 
respectively. 

After designing the antenna on paper one 




The ground plane and the angle brackets 
used to mount it to the mast. The wooden 
disk fits onto the mast of the heUx (70 cm 
helix shown here). The chassis mount type N 
connector is mounted about 2 inches off the 
axial center of the helix. Brass welding rods 
are used to support the hardware cloth. 



AUGUST 1975 



13 




The array support structure hefore its completion. The "X" structure is incomplete in 
this picture. Here the rotator (elevation) is mounted on the horizontal boom, which is 
subsequently attached to the *'X'\ Note the "T" structure on the ends of the *'X'\ The 
"X" is mounted so that each leg is on the opposite side of the horizontal boom, and this 
requires that wood spacing be put in between the two legs at the crossover point, 

mast with insulating supports (plexiglass) 
extending out from the mast at every 90 
along the turns of the helix. The pictures 
reveal the basic ideas and construction tech- 
niques, I used high quality 2 x 2 for the 
masts, treated v^ith linseed oil and painted 
with outdoor enamel after measurements 
and drilling were completed. The insulating 
supports are quarter inch thick, white plexi- 
glass; each support is about 1 inch wide and 
of an appropriate length for the antenna. 
This requires a total of (4n + 1) strips of 
plexiglass for n turns; I bought a large sheet 
of plexiglass and then cut it into small strips 
that were needed. Each strip was machined 
so that the conductor could be wound on 
these strips after they were mounted on the 
mast. Each strip has two holes drilled on the 
end that is to be mounted to the mast and a 
slot that will hold the conductor on the 
other end. The dimensions that yield the 
correct diameter and spacing after the strips 
are mounted and after the wire is placed on 
them is calculated from the geometry of this 
type of structure- It was necessary to make 
accurate measurements here as any errors 
would result in an egg shaped conductor, i.e- 
non-symmetric shape. The basic idea is to 



must find the most practical way to 
assemble it and also utilize available 
materials. I first thought of using copper 
tubing for the helix conductor, but after 
calculating the length that was needed and 
figuring the cost I was easily dissuaded from 
this route (for 2 meters about 6.8X of wire 
are used), I used three strands of 12 gauge 
copperweld wire* The next step in the 
process is to support the conductor and to 
engineer a support structure for the driven 
element that would be light, durable and 
structurally sound. The most important 
factor here is to preserve the symmetry of 
the helix, that is, to prevent the conductor 
from becoming egg-shaped. Also it is impor- 
tant that each turn is 1.00 wavelength long 
— here there is some room for error since 
small errors in measurements, mounting of 
the supports, etc., can throw off the circunv 
ference by as much as 0,1 OX (an accuracy of 
about ±.05X in the circumference is accept- 
able). Also, in designing a support structure 
for the driven element one must consider the 
ease or difficulty of winding or placing the 
conductor on the supports and securing the 
conductor firmly while adjustments are 
made. I decided on using a wooden antenna 



14 



73 MAGAZINE 



place the wire or conductor of the helix in 
the slot and to just wind it through so that 
the shape is very nearly perfect If my 
measurements were accurate, then the shape 
of the helix would be perfect, and I think 
that this success can be seen in the photos. 
After the wire is placed on the plexiglass 
supports and adjusted, a small piece of 
plexiglass is placed in the slot and per- 
manently bonded to the white plexiglass 
support. This small piece of plexiglass is !4 x 

Va X 2Y4 inches long colored plexiglass rod. 
An alternate and better way to support the 
wire is to drill a 14 Inch diameter hole and 
then wind the wire through. This has been 
tried on prototypes (both before and after 
this array was completed). Once the plexi- 
glass rods are in place and bonded, the helix 
conductor can stiti be adjusted, and is 
epoxied to the plexiglass supports. 

Since the helices for each band are of 
opposite sense, it was necessary to mount 
the plexiglass supports so that the sense 




The 2 meter helix, showing the plemglass 
supports and the rest of the mounting 
structure. Note the wooden disk, the hard- 
ware cloth, and the aluminum angle stodc 
used to construct the ground plane. The 
angle stock is mounted on the disk, after 
which the hardware cloth is attached to both 
the disk and the supporting structure. The 
feedline is seen behind the ground plane. 
The 'T" of the leg of the array support 
structure is attached to the mast of the 2 
meter helix with 4 Unbolts. 



would be correct. Also, it was noted that the 
wire used was wound in a right-hand sense, 
and when the left-hand helix was built it was 
necessary to uncoil it and rewind it in the 
opposite direction as it was placed on the 
structure. With the stiff wire, this turned out 
to be quite a difficult task. 

The ground plane essentially consists of 
hardware cloth that is mounted on a wooden 
disk before installation on the mast. The 
larger ground plane is supported by alum- 
inum angle stock. The ground plane 
diameter is 6 feet and 32 inches, respec- 
tively, for the 2 m and 70 cm helices. Two 
angle brackets are used to secure the ground 
plane to the mast. 

The feedpoint is slightly off center, but 
this does not critically affect the perfor- 
mance of the antenna {although it does 
appear in the antenna pattern). A better 
ground plane would consist of a metal plate 
with the connector mounted on the disk; 
this aluminum or brass disk could be square, 
with radials extending out to obtain the 
desired dimensions of the ground plane. 
Before the antenna array was installed on 
the tower, all metal parts were coated with a 
rust preventive (Val Oil), The antennas were 
completed separately and then installed on 

the array support structure, but before the 
array was installed, Cliff Burdette WA8GRE, 
of the Engineering Experiment Station, 

Georgia Tech, and I made far-field antenna 
pattern measurements which will be 

discussed later. The array support structure 
is shown in the photos. In order to put up 
the four helices this structure must be 
capable of supporting them and also rotating 
them. Basically the azimuth rotator is a 
TR-44 and is mounted on a mounting plate 
Inside the top section of the Rohn tower. 
The elevation rotator is an RCA 10W707 
rotator. This rotator is mounted horizontally 
in an azimuth-elevation system similar to 
that used in Reference 9. A better elevation 
system, like the system used by K6HCP 
(Reference 8), is desired, even though this 
system seems to work well. The horizontally 
mounted rotator is mounted via a small steel 
plate to a tower mast pipe that extends up 
from the azimuth rotator through the top 
section of the tower. This pipe is quarter 
inch wall 2-1/8 inch diameter steel, about 4 



AUGUST 1975 



15 



feet long, that was found in a local junk 
yard. Through the elevation rotator is placed 
a 1-1/2 inch diameter heavy duty, 10 foot 
length of conduit- The basic array support 
structure is built about this horizontal 
boom. This structure is basically an ''X", 
with a helix mounted on each leg of the **X" 
structure. The center or crossover point of 
the "X" is off center, and the horizontal 
boom about which the array is rotated in 
elevation is about 2,5 feet below this point 
The points where each of the legs cross are 
permanently secured to each other. Each leg 
is about 12 feet long^ and this makes the 
array about 11 x 11 feet. The legs are 
secured to the horizontal boom with a 
wooden disk and with U-bolts and lock- 
washers. The ends of the legs, where the 
helices are mounted, consist of a **T'* made 
of a small piece of 2 x 2, metal mending 
plates^ and a 6 x 6 inch piece of very hard 



wood. The larger helices are mdunted to the 
**T" with four U-bolts and appropriate hard- 
ware. The smaller helices are permanently 
mounted to the *T'"V A wooden brace is 
attached to the 2 m helices as seen in the 
photos- Also, a counterbalance, consisting of 
another 2x2 about 1 3 feet long, is attached 
to the upper part of the array where the 
smaller helices are mounted. Weights can be 
attached to this. The total array weighs 
about 80-100 pounds. Once the antennas 
were mounted on the structure, which itself 
was supported by a rope attached to a gin 
pole mounted at the top of the tower, it was 
necessary to get some help in order to haul it 
up. The feedline also had to be mounted and 
the swr checked out before the antennas 
were pulled all the way up and installed. 
The swr was checked by raising and lowering 
the array to a height of about 20 feet (more 
on this later). The tower on which the 




The support structure of the helix conductor or driven element The plexiglass strips are 
spaced every 9d^ along the turns of the helix. Also shown is the "T" u^d to attach the 
helix to the array support structure. The ground plane is to the left. Note the symmetry 

of the helix and also the small plexiglass rods on the ends of the plexiglass strips whew 
the conductor is mounted and epoxied to the supports. 



16 



73 MAGAZINE 



SAME ARRANGeMEMT THIS SIDE 
EXCEPT HELICES ARE OF 
OPPOSITE SENSE 



COUNTER 
BALANCE 




ROTARY 
JOINT 



■ TO AZIMUTH ROTATOR 

Fig. 4. Half-view of the updated version of the array, showing how the helices are mounted on the 

main boom and iUustrating the az-ei system and the antenna frame. The rotor is a Ham 11 mounted 
horizontally, covered to prevent the entrance of moisture. The main antenna boom is mounted at the 
top of the frame (or fork) through two bearings. This boom is rotated by the lever assembly. The 
rotary joints are tie rod ends (a surplus C141 assembly). At the bottom of the frame is the assembly 
that attaches to the azimuth rotor. Here a two inch inside diameter aluminum tube siips over a two 
inch outside diameter pipe, which in turn is attached to the other Ham 11 inside of the tower. This 
airangement eliminates major stresses and windmilling of any kind. 



antenna array is mounted Is a Rohn 25, 
with a section mounted in three feet of 
concrete- It is about 27 feet high and is 
non-guyed. To install the array f used a 
regular gin pole pfus a commercial gin pole 
designed specifically to be used with Rohn 
towers. The antenna array was hauled up by 
using a block and tackle hoist as well as the 
two gin poles. The last two feet were the 
most difficult, and eventually after much 
sweat and some very exasperating work 
hurrying to get the bolts secured, while the 
people on the ground held the array sus- 
pended in the air, the array was installed. 
Both the antennas and the array have been 
successfully subjected to hail storms and 
high winds -^ and even two tornadoes which 
passed through the area. 

Since the original construction and in- 
stallation were completed last summer, there 
have been some additions and changes in the 
array- First of all, during February 1975 
there were two severely damaging tornadoes 
in the Atlanta area. One struck the 
McCollum Airport, which is less than Yi mile 
from my QTH, and the other one destroyed 



a great part of northwest Atlanta, With the 
one that struck here in Kennesaw, my 
antenna array felt the high winds and hence 
suffered some damage. As I now travel most 
of the time as a sales representative, I came 
home to find that the tornado and the high 
winds left the array windmilling, i.e, rotating 
freely in the wind and fust barely attached 
by a safety (aircraft) cable that 1 had 
installed just in case this might happen. 1 
immediately lowered the array as I did not 
want it to fall if another tornado came 
through, f had been planning to lower it 
anyway to revise the az-el system and redo 
the basic mounting of the antennas. 

During May and June 1 redid the array. In 
my original instalfation the problems were 
mainly mechanical, i.e^ mounting of the 
antennas and rotating them in elevation was 
not as strong as I had hoped. Basically the 
new az-el drive and antenna frame, which 
can be seen in Fig, 4, was designed so that a 
large moonbounce antenna array could be 
rotated easily. A drive system like this has 
been used by DJ9JT (see Ref, 16). The basic 
arrangement consists of a frame, very similar 



AUGUST 1975 



17 




The 2 meter heUx as viewed from ground level with a telephoto lens. 



to a telescope fork, through which the main 
antenna boom is mounted. This boom is 
supported by bearings* The elevation drive is 
mounted in the lower part of the fork 
assembly. Here a Ham II mounted horizon- 
tally is to be used. A short section of tubing 
connects the drive motor to the mechanical 

arrangement used to drive the main mast, 
This is a basic lever; with the rotary joints 
being surplus tie rod ends. When the drive 
motor is engaged, the upper boom will 
rotate as does the lower boom, due to the 
lever-action, A chain drive could have been 
used instead of this particular arrangement. 

The main boom is 6061 -T6 aluminum 

tubing, with an o,d* of 2.5 inches. This 
boom is 21 feet long and all of the antennas 
are mounted about this boom. The fork was 
made up of surplus materials, mostly alumi- 
num, and was Hell Arc welded. At the center 
of the fork on the bottom side, a piece of 2 
inch i<d, 6061 -T6 aluminum tubing is 
HeliArc welded, A 2 inch o,d. pipe can be 
inserted and then secured; the other end is 
then attached to the azimuth rotor (Ham II), 
This fork assembly has eliminated major 
stresses that caused most of the problems in 
my original mount. Also, I have replaced the 



TR-44 with a new Ham IL The major 
problem is wind resistance, and since the 
Ham M has a 7,5 square foot rating as 
compared to the 2.5 square foot rating of 
the TR-44, this replacement has eliminated 
tendencies of the array to whip around in 
the wind (mainly the clamps slipped). I am 
also using the Ham II in elevation. This has 
also been successfully done at Phiico in 
Vandenburg^ California, as well as by 
Jacques Cousteau on his research ship* The 
major cost factor here was the rotors, as 
everything else used surplus or otherwise 
cheaply available materials, 

I have also modified the mounting of the 
helices. This time I did not use this "X" 
mounting as before, but used more of an 
"H" type mounting as seen in Fig, 4. 1 have 
also tried to make the array as lightweight as 
possible by redoing the mounting, adding 
counterbalancing, and by reducing the 
weight of the groundplane on the 2 meter 
helices. On the 2 meter groundplane: Here I 
have replaced the whole groundplane with a 
3/16 inch thick aluminum plate, about 15 
in. by 15 in., that has 8 radials of aluminum 
mounted on it. I also have a lighter mesh 
that is 4 feet by 4 feet, and this is attached 
to the radials which extend out as in the 



18 



73 MAGAZINE 



drawing. This reduced the weight consider- 
ably^ as I used really heavy hardware cloth 

on the original version. Also, I have 
remounted the helix so that the 2 meter 
helix can be mounted on the main boom. By 
having a 6 to 8 foot extension of 2 x 2 
beyond the balance point, I can counter- 
balance the antenna by adjusting a weight 
along this mast I have tried to mechically 
beef up the array in this process, and have 
also added a gin pole with a winch to lower 
and raise it. 
Impedance Matching 

The helix has a terminal impedance of 
140 Ohms and is pure rest sta nee • Since 50 
Ohm cable was used to feed the antennas, it 
was necessary to match the 50 Ohm impe- 
dance of the RG-8 polyfoam coax to the 
140 Ohm terminal resistance of the helix. A 
quarter- wave coaxial matching transformer is 
used as in Reference 4, The formula used to 
determine the correct impedance value is: 



where Zq is the desired impedance^ Zs is the 
transmission fine impedance, and Za is the 
antenna impedance. This is 83,7 Ohms in 
this case, and a value of 75 Ohms is very 
close. Here RG-ll/U was used for the 
matching section and RG-8/U polyfoam 
coax was used for the feedline. The match- 
ing section was made according to the 
formula: 



Length (feet) = 



246 V 



o 



= y 



Z5 Za Ohms> 



where V is the velocity factor for the 
RG-11/U (approximately .66) and f is the 
frequency in MHz, Two alternate and even 
better matching systems are described by 
Doug De Maw WICER, in Reference 4. Swr 
measurements were made with the antenna 
about 20 feet off the ground, and trimming 
the driven element was done by lowering the 
antennas within the reach of a step ladder. 
An initial swr of 1 J to 1.8 was obtained on 
the 2 meter helices, while a similar one was 
obtained on the 70 cm helices. By trimming 




The 70 cm heUx mounted on one of the legs of the antenna array support structure. The 
ground plane is 32 inches in diameter, and has brass welding rods as well as one piece of 
angle bracket for support. The ''T" structure is permanently attached to the mast. The 13 
foot long counterbalance is attached with a U-bolt to the leg of the "X". Besides acting as 
a counterbalance, the 2x2 keeps the two 70 cm helices from whipping around during 
wind or rotation. 



AUGUST 1975 



19 




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the driven elements, an swr of about 1.5 to 1 
was obtained. A better swr could be 
obtained if a matching section with an 
impedance of about 83 to 84 Ohms were 
used. 

To obtain a better match and hence a 
tower swr, 1 have talked with Mike Staal 
K6MYC, at KLM Electronics, about building 
a sleeve balun to match the 140 Ohm 
terminal impedance of the helix to 50 Ohm 
coax. By this time I will have either built 
one myself or else have had them made by 
Mike. The big problem in popularity of the 
helix has probably been the impedance 
matching, and since it is very easy to build 
the helices and get them working, it would 
be worth the cost of getting a sleeve balun 
made by someone who makes them profes- 
sionally. 

References 

[7] R. Mclain K9PVW,and K. O. Learner W9MDW, 
"Helix Antenna Guideline," AMSAT Newsletter, 
Vol. 4, No. 3, September 1973. 
[8 J Kenneth Holladay K6HCP, "A Practical Moon- 
bounce Array," Ham Radio, Vol. 3, No. 5, May 
1970, p. 52. 

[9] Wilfred Scherer W2AEF, "An Az-EI Antenna 
Mount," CQ, VoJ. 26, No. 11, December 1970, p. 
42. 

[lO] G. R. Jessop,"VHF-UHF Manual," RSGB, p. 
9.8-9.9. 

(11 J William Hale, L. DeSize, W. Offutt, "Methods 
of Obtaining Circular Polarization," Chapter 17, 
Antenna Engineering Handbooii. 
[12] T. Bittan G3JVQ/DJ0BQ, "Antenna Note- 
book," VHF Communications, Vol. 6, Spring 
Edition, 1/1974, p. 38-41. 

[13] Perry t. Klein and Jan A. King, "Res utts of 
the AM SAT-OSCAR 6 Communications Satellite 
Experiment." presented at the IEEE International 
Convention, New York City, March 28. 1974. 
[14 J Raphael Soiffer K2aBW, "Getting Started tn 
Satellite Communications: How and When to Work 
Through OSCAR 6 and OSCAR 7," AMSAT 
Newsletter, Vol. VI, No. 2. June 1974. p. 25-35. 
[l5j K. P. Timmann DJ9ZR, "A 5 Watt 
Transistorized SSB Transmitter for 145 MHz/' 
\/HF Communications, Vof. I, Edition 2, May 
1969, p. 73-82. See also "An 8 Watt SSB Trans- 
mitter Suitable for OSCAR 6 and OSCAR 7," \/HF 
Communications, Vol. 5, Edition 4, November 
1973, p. 228-233. 

t16] E. Reitz DJ9JT. "A Tillable Antenna with 
Selectibie Polarity", VHF Communications, Vol. 2, 
Edition 1, February, 1970, pages 12-20. 

Next month: Measurements and conclusions. 

. . . WB4VXP 



20 



73 MAGAZINE 




METER CRYSTALS 




STICK 



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money order. Master Charge, or BankAmericard. Orders prepaid are shipped 
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$5.00 each (Mass. residents add 15<^tax per crystal). 

We are authorized distributors for: loom and Standard Communications Equip- 
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We stock A/S and Mosley two-meter antennas 

We have thousands of crystals for monitor radios (Bearcat, Regency, etc.} along 
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Note: If you do not know type of radio, or if your radio is not listed, give either 
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LIST OF TWO METER CRYSTALS CURRENTLY STOCKED FOR 
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1. Drake TR-22 5. Ken/Wilson 

2. Drake TR-72 6. Regency HR-2A/HR212/Heathkit HW-2C2 

3. Genave 7. Regency HR-2B 

4. I com 8. S.B.E. 9. Standard 



The first two numbers of the frequency are deleted for the sake of 
non-re petative. Example: 146,67 receive v/ould be listed as - 6.67R 



being 



L6.01T 

2. 6.61R 

3. 6.04T 

4. 6.64R 

5. 6.07T 

6. 6.67R 

7. 6.10T 



8. 6.70R 

9. 6.13T 

10. 6.73R 

11. 6.145T 

12. 6.745R 

13. 6.16T 

14. 6.76R 



15. 6.175T 

16. 6.775R 

17. 6.19T 

18. 6.79R 

19. 6.22T 

20. 6.82R 

21. 6.25T 



22. 6*85R 

23. 6.28T 

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27. 6.34T 

28. 6.94R 



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31. 6.39T 

32. 6.99R 

33. 6.52T 

34. 6.52R 

35. 6.94T 



«u> u^ ^T^ Sv ^^r %&f ' 

^fm w^ ^^ ^m ^^ Jfn 



36. 7.60T 44. 7.72T 52. 

37. 7. OCR 45. 7.12R 53. 

38. 7.63T 46. 7.75T 54. 

39. 7.03R 47. 7.15R 55. 

40. 7.66T 48. 7.78T 56. 

41. 7.06R 49. 7.18R 57. 

42. 7.69T 50. 7.81T 58. 

43. 7.09R 51. 7.2 IR 59. 



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AUGUST 1975 



21 



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Ident alert 




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Adding a solid state display is accom- 
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as is the reset pulse. Q21, Q22 and Q23 
count these pulses and drive BCD-to-seven 
segment decoders^ QI8, QI9 and Q20, 
which, in turn^ drive the GaP displays. 

Each segment of each display must have a 
current limiting resistor between it and its 
driver output Rather than use twenty-one 
discrete resistors, the new resistor networks 
were used* These are thick film resistors 
fired on to a ceramic base. They have the 
configuration of an integrated circuit In 
Identalert Q ICRl, 1CR2 and ICR3 have 
seven resistors per package. R20 is used to 
light the decimal point. If available to you, a 
resistor network with 8 resistors (CTS 
761-3-R150) can be used for ICRZ 

My display was built in a separate 5" x 
2%" X 2]^*' minibox with a short intercon- 
necting cable (4-cond) running to the Iden- 
talert. Be sure to use no less than #18 wire 
for Vcc and ground wires. We are dealing 

*See "The Identalert", K2PMA, 73, April, 1975, p. 



with a fair amount of current, and voltage 
drops in the wiring can disrupt the operation 
of the display. 

Because the power supply is required to' 
supply approximately % of an Ampere 
instead of the 250 mA for the Identalert 
alone, it is necessary to make some extensive 
changes to the original supply. Just about all 
the parts used in the original supply are used 
and the parts designation numbers reflect 
this. Where an original part changes value it 
is noted in the accompanying parts list, i*e., 
R5 is 10 Ohm 10 W instead of 25 Ohm 10 
W, In order to use the original pass tran- 
sistor, 015^ it is essential that this device be 
attached to the chassis ^ which acts as its 
large heat sink. The original heat sink won't 
come close to keeping Q15 within its 
thermal rating. In addition, be sure that the 
box containing the power supply and the 
one containing the display have plenty of 
ventilation — a lot of heat is generated! 

After the supply has been built, connect 

about 6 Ohms (5 W) across the output and 
adjust Rl 6 and R1 7 for 5 volts. If there is a 
length of cable involved, connect the calibra- 
tion resistor at the display end of the cable* 
The parts list indicates two different types 
of trimmer. Whereas both will work, it is 
advisable to use cermet trimmers for their 
better temperature characteristics, 

I usually avoid using IC sockets, but did 
so in this case to mount the LED displays. 
The resistor networks and the sockets for 
the displays were mounted on a piece of 
punch board and this assembly was epoxied, 
at right angles, to another piece of punch- 
board on which were mounted the six ICs. 
The wiring from the networks to the display 



22 



73 MAGAZINE 



© 



3/- — v.** 

( °° ) 


4y- — X* 

I ^ ) 


I-WHITE 
i- GPN 
5-SLK 
4' RED 


2^^ ^1 


1^- — -^2 




' PLUG 


SOCKET 




FOR mi ERCOHHECT 

. * 





ICR 1-2-3 

flESlSTOR 

NETWORKS 



8YPASS CAPACITORS .WHERE USED, ON 
DISPLAY CHASSIS • Ol 

R20- DISCRETE tSOn r/4W 



5V 
ss 750mA 




CONNECTION TO 04 - 14 •■ (T) * 



CONNSCTION TOOb-5 "*'® 



Fig, I. Schematic, 



sockets was accomplished via #22 insulated 
wire; the same type of wiring was used from 
the networks to the drivers on the main 
board. There are a lot of wires in a small 
space, so some discretion is called for here to 
avoid shorts. Use a Discap to bypass Vcc for 

each two ICs, 

If you desire to vary the time cycle, wire 

in a single pole, 10 position, non-shorting 
rotary switch to Q7 and Q8 as shown in Fig. 
2. Remember, the Identalert counts seconds. 
For example, if your repeater times out at 2 
minutes 45 seconds, set the 07 switch at 1 
and the Q8 switch at 5. The Identalert will 
sound off at 158 seconds — 2 minutes 38 



07 



744 2 



g ;0 II I 2 3 4 5 e 7 




06 7442 


9 10 II r 2 14 5 67 






















b 


\, 


1 










L, 


.A" 










h. 


i_p 





012-1 



VIEW FROM SHAFT 
EMO SP-10P0S 
NOftI- SHORT 
{2 PLACES} 



Qt2-S 



seconds on the display. With this device in 
your shack, you'll never time out! If you 
add the switches, it is now possible to time 
events (within 0.1%) up to sixteen and a ha[f 
minutes. The display will show only minutes 
and seconds (not tens of minutes), but the 
"one" can be added mentally. 

The Identalert operates just as before, but 
now you can C how long youVe got before 
an ID or timeout. 



Fig. Z Switch decade. 







Parts List 


Displays 




OPCOA SLA 1 


ICR1. ICR2. 


ICR3 


14 pin DIP resistor network 
(CTS760-3-R150} 


R4, R20 




1 50 Ohm 'A W 1 0% 


R15, R19 




3.3k y* W 1 0% 


R18 




1 000 Ohm '/4 W 1 0% 


R16, R17 




1000 Ohm trimmer (CTS 

X201R102Bor 

360S102B) 


R5 




lOOhm low 


R12 




3^k 


C20 




50/35 V tytic 


Q16 




2N2219(hfe80orbetter} 


Q17 




2 N 3904 


Q18, Q19, Q20 


7447A IC 


Q21, Q23 




7490 IC 


Q22 




7492 IC 


Fl 




t A 

. . . K2PiVIA 



AUGUST 1975 



23 



iV 



There are several good transceivers on the mar- 
ket today. But if you compare them carefully. , , 
study the specifications, note the important 
features, and finally tafk to some Kenwood own- 
ers, you will have to come to the same conclu* 
Sion that thousands of others have come to. . . 
you can't buy a better rig for the money than a 
Kenwood. Every unit is built with pride and 
designed to give top performance year after 
year. Join the switch to Kenwood. 






iMHWS 



24 



TheTS-520 shown 
with the VFO 520 and SP-520 

The TS-520 is the final word in SSB transceivers 
... the ''hottest little rig on the air," It is a com- 
pact, mostly solid state, all-in-one transceiver 
with built-in AC/ DC power supply and speaker. It 
operates SSB and CW on 80 thru 10 meters. 
Features include 2-position ALC and double split 
frequency controlled operation. 

Available at select Kenwood dealers throughout the U.S* 

Distributed by 



■ ■ ■ 



TRIO-KENWI 
COMMUNICATIONS INC. 




V • 



116 East Alondra / Gardena, California 90248 



73 MAGAZINE 



Peter A. Stark K20AW 

1 96 Forest Drive 

Ml Kisco NY 10549 



Digital SWR Computer 



Part One 



Ask two different designers to design some 
particular device, and quite likely they will come 
up with two circuits as different as night and day- 
It can sometimes be very interesting to compare 
these circuits to see just how they approach the 
same problem. 

In the November and December 1974 issues of 
73 Magazine, Terry Mayhugh W60TG described his 
design for a digital swr computer. Shooting for the 
best possible accuracy practicaIFy aveifable, hts 
circuit used 27 ICs, not including those in the 
power supply. This included some rather exotic op 
amps^ an analog multiplier IC, and a digital-to- 
analog converter, as well as a variety of precision 
metal film resistors. K20AW, on the other hand, 
says that he was primarily concerned with making 
his digital swr computer simple and easy to build, 
even if it might provide slightly less accuracy. His 
circuit uses 11 ICs (plus one in the power supply)^ 
all of them standard, easy-to^et. In addition, his 
article provides the layout for a printed circuit 
board about 4 x 6", which mounts all components 
except for the transformer and directional coupler- 
Measurement of swr requires a directional 
coupler in the transmission line, which provides 
two voltages, called Vp and Vr, proportional to 



the voltages traveling in the forward and reverse 
directions, respectively. The swr is then computed 
from the equation: 



Swr = 



Vp + Vr 

Vp - Vr 



W60TG uses precision operational amplifiers to 
sum the two voltages to provide the top term In 
this equation, and to subtract the two voltages to 
provide the bottom term. An analog divider circuit 
then does the actual division, and a simple digital 
voltmeter converts the resulting voltage into the 
displayed digital swr reading, 

K20AW starts off with a similar approach, also 
using op amps to provide the sum and difference 
terms In the equation. But then, instead of doing 
an analog division^ he converts the two voltages 
into digital signals and does the division digitally. 
This eliminates several hard-to-get components, 
and also simplifies the digital readout circuitry. 

To sum up, weOTG's circuit, if properly built 
and aligned, can be somewhat more accurate, while 
K20AW's circuit is simpler and easier to build. 
Even if you don't decide to build either, we feel 
that you can pick up many useful hints by 
comparing the two designs, — Ed. 



Swr measurements are a common part of 
an amateur's life. Most active hams have 
an swr bridge of one kind or another, and 
often use it to adjust antennas, feedlines, 
matching networks^ or other parts of their 



antenna systems. Even when everything is 
finally done, an swr measurement is a useful 
check to make sure everything is still work- 
ing properly. 

Unfortunately, swr measurements are 



Al irii ICT 1 QIC 



7^ 



simple but awkward* The more affluent 
hams may have an in-line wattmeter which 
can measure something called ^'forward 
power'* and "reflected power/' Once these 
values are read, they have to consult a table 
or do a short calculation to find their actual 
swr. On the other hand, most of us have a 
simpler ''swr bridge/' which is normally 
operated by placing a switch in the **for- 
ward" position, adjusting a pot for a full- 
scale meter reading, and then flipping the 
switch to the ''reflected" position to get a 
reading. 

Both of these methods are awkward and 

time consuming. Though they are simple, 
some time is required for each reading — and 
it is hard to make adjustments and take 
readings at the same time. There is no 
such thing as slowly adjusting some com- 
ponent while looking for a null in swr — you 
have to alternately adjust, take a reading, 
adjust, etc. 

Thus there is a need for some sort of swr 
indicator which can give you a continuous 
reading without the need to flip switches or 
adjust pots. Though such a device exists 
commercially — it is a dual-pointer meter 
where one pointer reads the forward power 
while the other pointer reads the reverse 



power at the same time — it is expensive and 
still difficult to read accurately and fast. 
This article describes another approach to 
the problem of fast and accurate readings — 
a digital swr computer which automatically 
computes the swr and displays it on a digital 
readout automatically every time you 
transmit The swr computer is specially 
valuable when making any kind of antenna 
or transmission line adjustments, but it can 
be left in the line permanently to give you a 
day-to-day check on the performance of 
your antenna system with just a glance at 
the digital readout 

The swr computer uses a directional 
coupler inserted into your transmission line 
in the same way as any swr bridge. In fact, 
you may use your present swr bridge just by 
making three connections to it: bringing out 
a ground, the forward voltage (Vp) and the 
reverse voltage (Vr). The computer then 
calculates the swr from the formula: 



Vswr = 



VF + vr 

Vf - Vr 



and displays it as a three-digit number 
between 01.0 and 99:9 on a light emitting 
diode (LED) readout. 

All the parts mount on one 4x6*' printed 
circuit board, except for the directional 



ANTENKA 



TRAI^SMITTER 



DIRECTIONAL 
COUPLER 

1 



V 



/77 



V FORWARD 
tVF) 




m 



^pe 



y^ 



V REVERSE 
fVR) 



VF + VR 



RE 



VF 



>^ 



VR 



VOLTAGE TO 

FREQUENCY 
CONVERTER 



VF 



Vft 



INVERTER 



> 



-VR 



/ 



VF - VR 



VOLTAGE TO 

FREQUENCY 
CONVERTER 



>. 



R3 



SUM 



LED 
DISPLAYS 



I 



DECODERS/ 
DRIVERS 



I 



COUNTERS 



DIFFEREMCE 



tIO 



OVER- 
RANGE 
CIRCUfT 



J 



Fig. I, Block diagram. 



26 



11 AflAn A^IM 



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LARGE SCALE USE OF ICs IN 
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Engineered and built in U.S. — Top 
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FACTORY DIRECT SALES & SER- 
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FEATURES 
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Reverse polarity protection * Final tran- 
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for unusually good sound * Ext. spkr. 
jack * Front and rear antenna jacks * 
Rugged but light — 2 lbs. * Size 
2ViX6X8" * Electronic T/R-no relay 
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* Super eff * xmtr — dravws only 900 mA 
@ 5W, out * High quality Ceramic mic * 
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0,3uV/20dB Qt.* Incredibly sharp IF, at 
least -SOdB @ t30 kHz * Single Conv. 
Rcvr. — superior to dual con v. designs 
for spurious resp. rejection f * Very easy 
to service. 



See Review Article in April 73 Mag. 
Send Card for Data Sheet. 




OUSE IT PORTABLE - OVER THE 

SHOULDER - with the BP-1 IMicad 

Battery ''SNAP PACK'' 
atySE IT MOBILE with the BA-1 25 

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$199 
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95 



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A limited number of units are In Stock for Immediate Sfiipment. 
(Aifow 2 wks for personal checks to clear.} 



r 



Inquire about our: 

• Package Deals 

• SCR- 100 Repeater 
Receiver Board 

• SCT 100 Trans 
mitter Board. 



eANMMERICMol 



l/tt tr-t in * 



masler cliarge 



Please ship the foUowing: 

nsC512 @ $199.95 
nSC560@ $179,95 
QMB-I Mobile Mount @ 

$7.95 
D BP-1 pkg, (Btry pack, 

chgr., ant., carrying 

stp) @ $79.95 
DbA-1 Amp @ $84.95 
a AC'1 Sply. @$44,95 




SCSI 2 W/BP'1 "Snap Pack" 



Amt. End. $. 



OSCR100@ $89.95 
O Precision Xtals ±0.001% 
® $4,95 
(List on separate sheet) 

Name 



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SPECTRUM COMMUNICA TIONS 

BOX 140, WORCESTER PA 19490 (215) 584-6469 



^ 






I 



fon^ARD 



01 



REVERSE 




;470 



E f -i 



.002 



^\ 







22K 



/ff 



DIFFERENCE 



-2 



03 




■□ 



Fig. 2. Input circuitry. The resistors labeled '*1 ", "2'\ 
and "3'* are to be three matched pairs. 



coupler, a 6,3 volt power transformer, fuse, 
on-off switch, and line cord. The computer 
is therefore very easy to build and trouble- 
shoot, since the printed circuit board elim- 
inates 99% of your problems. Calibration 
consists of adjusting only three potentio- 
meters. 

The estimated price of the parts listed at 
the end of the article is about $40, assuming 
that you shop carefully, (By limiting the swr 
computer to a two-digit readout instead of a 
three-digit readout — a maximum swr of 9,9 
rather than 99*9 — you can save about $5. A 
much greater savings can be made if you 
already have, or intend to build, the K20AW 
frequency counter — you can save about $30 
by using the counter as the readout device.) 

How It Works 

Fig, 1 shows the block diagram. We start 
with a directional coupler, shown in the 
upper left corner. You may build your own 
following the ARRL Handbook or any of a 
number of other designs, or you may use a 
commerciafly available swr bridge, such as 
the $12 Lafayette bridge. 

The coupler, using a combination of 
inductive and capacitive coupling, provides 
two output voltages called Vp and Vr, 



which represent the forward and reflected 
voltages. These are tapped off the coupler 
circuitry at the output of the signal diodes^ 
as shown in Fig. T {Note: Make sure the 
diodes are oriented as shown to provide a 
positive output voltage to the computer*) 
For calibration purposes, the Vp and Vr 
voltages go through Rl and R2, two adjust- 
ment pots. An \C inverter changes Vr into a 
negative voltage -Vr and two IC analog 
adders then provide the sum voltage Vp + 
Vr and the difference voltage Vp - Vr. 

These two voltages are then fed into two 
voltage-to-frequency converters, which pro- 
vide a pulse signal whose frequency is 
proportional to the applied voltage, R3 
allows adjustment so that the two converters 
track each other. The difference frequency is 
then divided by 10 in a digital divider and 
both signals are applied to the counters. 

The counters are three stages of 7490 
decade counters, which count the input 
pulses arriving from the sum circuit. These 
counters can count from 000 to 999, and a 
decimal point is inserted on the LED display 
so that the count is displayed as 00.0 
through 99.9. The resulting count is fed to 
the LED display through I C decoder/drivers. 
If the count ever exceeds 799, the overrange 



28 



73 MAGAZINE 



+5V 






IC7 
7448 



b 
c 
d 



f 



13 



12 



lO 



i — j 



m 



\4 




B 



J^ 




IC9 



7448 



a 

b 
c 

f 

A B C D 



abcdef g 

^ COMMON- 
CATHODE LED 



4,12 



14 



P2 



9 



e 



(3 



i£ 



II 



10 



9 



15 



14 



H 



)3 



& 



390fl 






o b c d e f g dp 

COMMON- 
CATHODE LEO 



Jr 




4,l£ 



A B C D 

S^ 1C8 
7490 



I 2.5 1 6,7. 



1^ 



12 



abed B f Q 

COMMON- ^Ppili 
CATHODE LED [^ 



J 



4,12 



'^ 



8 N 



A B C D 

bd 

Q EC 10 

7490 



.*5 



|£.5 |e>7, 



+ 5V 



+ 5V 



4.7K 




4,7K 



06 *5V 

2N706 



lfM9l4 




05 
2M706 



Fig. 3- Display circuits. 



circuit lights up all the decimal points 
indicate that the swr is very high. 

The actual division in the formula: 



to 



Vswr - 



VF + VR 
Vp - VR 



is done in the decade counters digitally, by 
allowing the difference frequency to reset 
the counters back to zero. To see how this is 
done, let's work through a simple example. 
Suppose that the forward voltage Vp is 3 
volts, and the reverse voltage Vr is 1 volt 
This condition represents an swr of 2. 
Depending on how the adjustment pots are 
set, let us suppose that the sum signal, Vp + 
Vr, will be 4 volts, while the difference 
signal, Vp - Vr, will be 2 volts. Then, since 
the voltage-toTrequency converters are 



reasonably linear, the sum frequency may be 
1000 Hz, while the difference frequency 
would be half that, or 500 Hz. 

Hence the counters get the 1000 Hz 
signal to count, but are reset back to zero at 
a 50 Hz rate (since the 500 Hz signal is 
divided by 10 before reaching the counters). 
Thus the counters will only reach a count of 
020 (which will be displayed as 02.0) before 
being reset back to zero. In this way, the 
display shows the true swr. As with any 
counter, any reading is correct to within one 
digit, while the voltage-to-frequency conver- 
sion process is linear to within about 1 or 2 
percent — so the overall accuracy of the 
computer is easily within a few percent. 

Fig. 2 shows the input stages of the 
computer. Except for IC3, which inverts Vr 




IIOV 



^ 



63V 
3A 



Tie 



500^ F 
25V 



% 



frl 



IN400J 



b* 



* + 9V 




rn 



15V 



2200>i^F 

iSv 



777 



+~r25V 



aoo^F 



Fig. 4. Power supply. 



- 9V 



f 



■* + 5V 



10^ F 
15V 



/77 



AUGUST 1975 



29 




Fig, 5(a), Pc board (fuil size). 



into -Vr, the sum and difference circuitry is 
identical. In the sum circuits, ICI adds Vp 
and Vr, and drives a 2N3638 transistor, 
which acts as a constant current source to 
charge a 0.01 uF capacitor (which deter- 
mines the frequency at which the 2N4891 
unijunction transistor oscillates). The 
current which charges the capacitor goes 
through the 10k resistor in the emitter of 
the PNP transistor; this produces a voltage 
drop which is fed back to the input of ICl as 
negative feedback, making the overall 



voltage- to- frequency conversion very 
accurate, IC4 then divides the difference 
signal's frequency by 10, 

Fig. 3 shows the counters, decoders and 
drivers, and displays. Except for the opera- 
tion of IC5, the circuitry is very straight- 
forward: IC6, 8 and 10 are the three decade 
counters, IC7, 9 and 11 are the decoder/ 
drivers. 

IC5a and IC5b control the counting and 
display functions. Suppose the difference 
frequency coming in at the B input is 50 Hz, 



30 



73 MAGAZINE 



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Ai iCLV ICT 1Q7R 



%\ 




Fig. 5(faJ, Parts layout 

that is, a pulse arrives every l/50th of a 
second (every 20 milliseconds). lC5b is 
connected so that it flips at every input 
pulse, so it will be on for 20 milliseconds, 
and off for 20 milliseconds* 

While IC5b is on, its output on pin 12 is 
positive, which is sent to IC5a; this allows 
IC5a to accept the sum pulses. IC5a acts 
with IC6 to count the input pulses, so during 
this 20 milliseconds the counter is working. 
If, as in our above example, the sum 
frequency is 1000 Hz (the sum pulses arrive 
1 millisecond apart), then 20 pulses will 
arrive during this time, and the counter will 
count to 20. But pin 1 3 of IC5b connects to 
IC7, 9 and 1 1 in such a way that the displays 
are turned off {a zero voltage is applied to 
point E, which feeds the BI — Blanking 
Input — on these ICs). Hence the displays 
don't indicate anything at this time. When 
the 20 milliseconds are up, IC5b flips to off. 

With \C5b off, IC5a is prevented from 
counting as it gets zero volts at its JK inputs, 
so for the next 20 milliseconds the counters 
stay at the value they reached at the end of 



the counting interval At the same time the 
Bl inputs to the decoders go positive, so the 
LED display shows this count. At the end of 
this time interval, when IC5b again goeso/?, 
short pulses are sent through the two 500 pF 
capacitors which force lC5a, IC6, ICS and 
ICIO back to a count of 000, so that the 
next count starts again with 000. 

The only unexplained circuit is transistor 
Q6 connected to IClO- As soon as the 
counters reach a count of 800, pin 11 of 
ICIO goes positive, which charges up the 10 
uF capacitor connected to the transistor's 
base; this in turn connects a positive voltage 
to the decimal points on the first and third 
LED digits to indicate a very high swr. 
Actually, the swr is too high much before it 
gets anywhere near 80^ and the purpose of 
this circuit is not to tell you which swr's are 
OK and which are not Rather, the purpose 
is to warn you in case the swr might be 
computed as something like 101 or 102. 
Since the maximum swr which can be 
displayed in the three digits is only 99,9, an 
swr of 101 would be shown only as 01.0, 
with the first 1 missing. The extra decimal 
points are there to warn you of this condi- 
tion. 

Fig. 4 shows the power supply, which 
consists of a standard bridge and !C voltage 
regulator to generate +9 and +5 volts, and a 
modified voltage doubler to generate -9 
volts. See the Parts List for comments 
regarding the power transformer and the 
heat sink for the regulator. A perfectly 
adequate heat sink, if the IC is mounted on 
the board, is a 1 x 4" piece of aluminum, 
bent into the shape of a squarish U, and 
mounted under the IC so that the ends of 
the U stick up off the board. Alternatively, 
the IC can be mounted on the cabinet 

Construction 

With the exception of the power trans- 
former and the ac line components, alt the 
components shown in Figs. 2 throu^ 4 
mount on the printed circuit board as shown 
in Fig. 5. Note the following points before 
starting to mount the parts: 

1) The 500 uF and 2200 uF capacitors in 
the power supply mount upright; axial lead 
capacitors will work, though radial lead 
capacitors fit better 



32 



73 MAGAZINE 



SOCKET LED 







PC aOARD 

Fig, 6. Alternate LED mounting^ 

2) IC sockets or Molex Soldercon pins 
should be used under all ICs and LEDs, Our 
own preference is Molex pins, as 8-pin 
sockets for the 741 ICs are difficult to 
obtain. Moreover, many LEDs have round 
rather than flat pins, and do not fit into 
most sockets. 

3) The twenty-two 390 Ohm resistors 
near the LEDs are quite crowded, and some 
can lie flat against the board while others 
have to be mounted standing up. Be 
especially careful while mounting these 
resistors to leave room for those resistors 
still to come* 

4) The LEDs are shown as being mounted 
flat against the board, like ICs. This would 
be an appropriate way of mounting them if 
you intend to look at the LEDs from the top 
of the board. Observe especially how the 
LEDs mount — with pin 1 of each LED 
towards 06- The proper way to hold the 
board for correct rightside-up display is with 
the LEDs in the lower left corner. In order 
to be able to mount the board closer to the 
face of the cabinet, you may wish to place 
the standup electrolytic capacitors on the 
wiring side of the board. Either sockets or 
Molex pins may be used for the LEDs, but 
make sure that the sockets you use will 
accommodate the LED pins. 

On the other hand, the LEDs can be 
mounted vertically as shown in Fig, 6^ by 
using short wire jumpers either with a socket 
or soldered directly to the LED pins. 
Though somewhat more laborious, the latter 
mounting method is more convenient if you 
intend to mount the board horizontally in a 
cabinet and look at it from the front edge. 

5) Most of the jumpers on the board are 
straight point-to-point wire jumpers, but 
there are two which have to span several 
inches; these connect the two points labeled 
C and D near the LEDs to the two 1 20 Ohm 



resistors near the edge of the board. You 
may place these two either on top or under 
the board, but make sure they are insulated. 
. 6) The LM309K IC mounts on a U- 
shaped heat sink made out of a 1 x 4" piece 
of aluminum (or a Wakefield sink can be 
used — see Parts List). It can also be 
mounted on the cabinet, in which case no 
heat sink is needed if the cabinet is metaL 
The case of the IC is grounded^ so no 
insulators are needed. 

7) To reduce the possibility of errors^ a 
small dot on the printed circuit board 
identifies pin 1 of ICs, the positive terminal 
of electrolytic capacitors, and the cathode 
terminal of diodes. 

8) In accordance with good design 
practice, a number of 0.01 uF capacitors are 
scattered throughout the board, connected 
between the +5 — volt line and ground; these 
are generally not shown on the diagrams. 
Small 1 or 25 volt units are quite adequate, 
and are recommended because of their small 
size. In this application their exact value is 
not important, and anything from 0.005 to 
0.1 uF should work, 

9) The 0.01 uF capacitors connected in 
the timing circuit (the emitters of the 
unijunction transistors) are important in 
determining the long term accuracy of this 
unit. Though their capacity is greatly depen- 
dent on temperature, disc ceramics will work 
here quite well (as long as they are the same 
brand and type) since the two capacitors 
should track each other and thus compen- 
sate, to a large extent, for each other. 
Nevertheless, if you are really concerned 
about accuracy, you might want to consider 
a more stable capacitor type for this applica* 
tion, such as a polystyrene or mylar capaci- 
tor. 

10) The six 27k resistors determine op 
amp gain^ and must therefore be carefully 
chosen. They need not be exactly 27k, but 
must be selected ^s matched pairs. Each pair 
is connected to one of the 741 op amps, and 
the resistors to be matched are shown in Fig, 
2, The best way of matching the resistors is 
with a digital VOM or an accurate bridge, 
but even a fairly good VOM should be 
adequate. 

11) Under certain circumstances, the 
digital circuitry may be susceptible to rf 



AUGUST 1975 



33 



interference from your transmitter. When 
mounting the board in an enclosure, keep in 
mind the future possibility that bypass 
capacitors may have to be added to all 
inputs — signal and power, 

PARTS LIST 

Integrated Circuits 

3^741, 1-7473, 4-7490, 1-LM309K, 3-7448. 

Resistors 

10% % Watt: 2-120, 22-390, 2^70, 1-1k, 2-2,2k, 
44-7k, 2-1 Ok, 3-1 2k, 1-1 50k, l-IOOk; 
1% % Watt: 6-27 k. These resistors need not 
actually be 1% tolerance^ but for best accuracy 
should be matched pairs. They can be 10%, as their 
actual resistance is not too important as long 35 
they are in matched pairs. 

Potentiometers 

2-1 Ok and 1-1 00k, upright printed-circuit type, 

such as CTS type (avarL at Radio Shack J. 

LED Readouts 

Three common-cathode DL-704, MAN-4 or equiva- 
lent LEDs; other common-cathode LEDs can be 
used, though board layout may not fit other pin 
connections. Common-anode LEDs can be used if 
7448 ICs are changed to 7447, 390 Ohm resistors 
are replaced by 220 Ohms, and a different set of 
connections is used between 7447 and LEDs, 

Capacitors (those marked * are upright mount) 
Disc: 2-500 pF, 2-0.002, 12-0.01 ; 



Electrofytic: 2-10uF 10 V, 2-500* uF @ 16 V, 
2-2200* uF 16 V. 
Transistors 

2 '2 N 706 NPN switching transistors or equivalent; 
2-2N3638 PNP or equivalent, but must have fairly 
good beta; 

2-2N4891 unijunction (Radio Shack R 3^2029). 
Diodes 

1-1N914 or 1N4145 silicon signal diode orequiva* 
lent; 

6-1N4001 rectifier, 1 Amp 50 piv or equivalent- 
Transformer 

6.3 volts at 3 Amps. Actually, only about % 
ampere is required, but 6.3 volts is a little marginal. 
If you can get a 7 or 8 volt transformer, then a % 
Amp transformer will do. Otherwise, a 6.3 voit 3 
Amp transformer under this very light load will 
provide about 754 volts, which is OK, 

Assorted 

Line cord, fuse, on-off switch, wire, solder, 
cabinet, display bezel. Wakefield NC-631-3 or 
equivalent heat sink, if LM309K is mounted on 
board; no heat sink required if it is mounted on the 
cabinet. Also needed is any type of home brew or 
comrr^rcial directional coupler or "swr bridge." IC 
and LED sockets or Molex Soldercon pins are 
helpful. Printed circuit boards may be made from 
Fig. 5; etched and drilled boards are also available 
from Star-Kits, G.P.O. Box 545, Staten Island NY 
10314. 

Hext month: Operation and calibration, 

. . . K20AW 



^m^ 



^ 







Pc hoard with components. 



34 



73 MAGAZINE 



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AUGUST 1975 



35 



Bill Hoisington Kl CLL 
c/o 73 Magazine 
Peterborough NH 03458 



RF Feedback^ 
The Experimenter's Curse 



There is a parti culariy nasty form of 
trouble which can afflict solid state 
transmitters, and multi-rf stage receivers too^ 
much more than the old-fashioned tube jobs, 
and considerable attention must be paid in 
order to avoid it. This is interstage coupling 
through the low impedance power lead 
connections and wires, which ordinarily with 
tubes would not allow sufficient rf voltage 
to be sent from stage to stage to cause much 
trouble. 

Even with tubes^ precautions against this 

type of trouble had to be taken at timeSj 
especially as one went higher and higher in 
frequency up into UHF. One of the bad 
features about it is that it can happen 
easily enough between a first stage and a 
last stage, transforming one millivolt into 
one volt and causing violent reaction. 

Very complicated power lead filters have 
been devised for this deal, as for example 
eight and sixteen section filters for an eight 
tube radar i-f strip. 

Ceramic feed through bypass capacitors 
were designed for use where power leads 
went through partitions, which cut down 
the nuisance rf voltage to a certain extent, 
enough for the tube type sources, exciters, 
and finals, if sufficient care and shielding 
was used in the overall design. Some of 
these ceramic feedthroughs work at 432 
and some do not, as you will see. 

Now we are faced with devices (trans- 
istors) which exaggerate this kind of 
trouble due to vpry low rf impedances. 



Some transistor collector circuits operate 
vrith impedances of less than ten Ohms, and 
for high power it may go under an Ohm. 
This means that a bypass, that was good at 
432 MHz with tubes, may let through rf 
voltage at low imp>edance, driven by tho^ 
high current sohd state devices to couple 
back from the final right past a "bypass" 
capacitor and into the exciter and knock it 

ri^t out, subject to the phase involved. Or 
worse, throw the stages into self -oscillation, 
because the input of these devices is also low 
and so operates on very small voltages of just 
the kind we're talking about, Tliis is further 
aggravated if low cost devices are used in the 
first stages because then the low level opera- 
tion is more subject to feedback. 

Say you've got a gain of 10 or 12 in each 
of two rf stages, the last one putting out one 
or two hundred milliwatts, and you couple 
back just one percent along the battery leads 
to a tripler stage with an output of only one 
or two milliwatts. You see what can happen? 
And it does, too! Not only that, but if it just 
happens to be in phase, you get output even 
when you pull the crystal out, and that is 
about the worst thing that can happen to 
any transmitter. 

So it will pay to examine this question 
in detail, because as amateurs we have an 
obligation as well as the need to develop 
our skills in the art, and this subject is a 
basic one for all types of transmission and 
reception by solid state devices. 



36 



73 MAGAZINE 



With this in minds J started in on the 
power lead filter deal with the goal being a 
small low-cost unit easy to make, with at 
least 40 dB of attenuation in voltage, if 
possible. It turned out that it was. 

These tests and the final low cost filters 
are good for receivers also. A contemporary 
author in another magazine 1 happened to 
be reading recently mentioned, "You*ll 
have an easier time with one rf stage than 
with two," No argument there at all. Just 
that these tests and filters should help 
reduce the effort needed to "tame" two rf 
receiver stages, as well as multi-stage 
transmitters. 

How to Get **Co!d" Connections 

Most of our work on UHF calls for hot 
wires, that is, wires carrying plenty of rf, 

and losing the least amount possible 

through insulation losses, radiation, wire 

resistance, or by any other nuisance 

method. For power leads we want just the 

opposite, to carry dc and lose all the rf 

immediately- Or at least so much that you 

can neither detect it, nor find any nuisance 

effects, which amounts to the same thing. 

An oscillator and rf amplifier will do for 

the source and a tuned diode detector will 

do the job of measuring. After all, we're 

not doing a research job for a capacitor 

company, we're just interested in learning 

how to put a solid state transmitter on the 

air with a good stable signal without 

touchy feedback, connectors that jump 

rf'Wise, and other transmitting plagues. The 

same holds for the multi-stage receiver also. 

Fig. 1 shows a test set-up that can tell us 
what's what in this matter. After all, if I do 
it and tell you about it, that gives you more 
time to build things and get them on the air. 

At "A'* we have a good 20 mUli watts at 
432 MHz coming onto the test plank. At 
**B" we have another cable going to the 
tuned diode detector, and with the units 
shown the meter reads four volts dc when 
"A" is connected to "B," 



CRYSTAL 
OONTROLLED 
SOURCE 
43S MHi 



DC MICftO-AMMETER 
CALIBRATED IN 
Oe VOLTS 




Tlie trick is to connect something' 
between A and B that will carry heavy 
current 1 2 volts dc with only a small drop or 
none at all. This may mean a thin wire 
choke, or a resistor for a low power first 
stage drawing only 10 or 20 milSj and it may 
mean later a heavy wire choke for 12 volts at 
one quarter of an Amp for a three Watt 
final. 

Tests 

Referring to Fig, 1 , all results are given in 
dc volts at the output of the diode detector: 

Coaxial cable A to B, 4 volts; piece of 
wire on the ground^ 3.5; piece of wire with 
1000 pF to ground at B, 3; 1000 pF at A, 
.29; 1000 pF at A and B, ^04 (40 milliwatts); 
100 Ohm resistor between A and B, .042; 
with 1000 pF at A and B, plus 100 Ohms 
between A and B, zero volts. This could be 
used with a low current stage like a receiver 
where even down to six volts is all right for 
low noise rf^ but let's keep going. You 
certainly couldn't modulate a solid state 
final through a 1 00 Ohm resistor. 

Choke coil between A and B^ no, 40 wire, 
Va^ diameter, length Vi", no capacitors, .2; 
with 1 000 pF at A, .01 volts; with 1 000 at A 
and B, Vi mV. Beginning to look good. 

10 turns no. 34 wire, 20 mV, showing 
that the choke question is subject to varia- 
tions in filter power, in this version. 

Yellow surplus choke, 1 mV, good but 
not quite the ideal yet. Ten turns on the 
choke and 1000 dipped mica at A and B, 10 
mV. Same, with small 3/ 16th Lafayette 
ceramics, 3 mV, 







/ 


f — r- 1 H 


Fbhr^LA^^ 


BRASS— ^s. 




V 


^.^ BRASS PLATE 


^*nl 






j,^^ 


^ 


^ 


-^ 


y— SOLDER 








J±M . iJ 


fdlllJUlkkLkklbk 





7 



GROUND 



z 



SOLDER LU6 



Fig. 2. Simulated, flat coaxial filter^ 



RFC 



TERWINAL STRIP 




C=r|000 pF 



Fig. I, Test setapt power lead filters. 



Fig, 3, Filter module. 



AUGUST 1975 



37 



C * iOOO pF 
t4 REQ'D} 



1/2 ta, HOLE (Tm 




10 TURNS OVER 
lOOKJ W RESISTOR 



SOLDER TO aAS€BOARO 



Ry. 4, Brass frame module. 

Home-brewed flat coax, as in Fig* 2, 10 
mV; two 1000 pF at A and B^ plus 20 turn 
choke, 1 mV, At this point I thought about 
a smaU module as in Fig, 3* The meter hit 
the pin. Brining the two capacitor to one 
connector^ which had some inductance to 
ground, was absolutely N,G* 

I then cut out a small brass frame as in 
Fig. 4, Hurray! The first time to hit a real 
zero volts. It makes you haul out the 
ohm meter and check for a short or an open! 
Same, but without choke, ako zero. 

I noticed that every time I checked with 
another 1000 pF on a little coffee stick from 
A or B to ground. In effect paralleling the 
one already there, the meter plunged to near 
zero. At 432 MHz this is the same thing you 
may have read about more than once in my 
articles. More than one capacitor at the same 
place. It parallels the inductance and drops 
it. 

Now weVe getting close to the ideal; in 
fact, to cut it short. Fig. 5 shows the ideal. 

No brass plate is needed, and you can use 
it either on the baseboard or with the 
choke-resistor installed in a hole in a box 
wall, or what have you. 

The two-section filter, using 4 capacitors 
plus a choke in between, really does the job. 
You imagine the meter moves, maybe. There 
might be somewhere between I/IO and 
1/100 of a rmllivolt of rf leaking through, 
and some or aH of this may be **jumping" 
through the air. 

So now you can make up units in 
advance, as in Fig. 5, and be sure they^ll 
work at 432 MHz. 

30 pF Capacitors 

Just for fun, another two-section filter 
was assembled, as in Fig, 5, but with the low 



> 




MWMWWW 




SOLDER TO BASEBOARD 
{A PLACES) 



Fig. 5 A, Ideal low-cost power lead filter, top view. 




BASEBOARD (GROUND) 



-mmumm- 



t 



Fig, SB, Side view of power lead filter. 

value of 30 pF for each of the four 
capacitors. Of course at 432 MHz the rf 
impedance of 30 pF looks almost like a dead 
short, and it was. I could not tell the 
difference between the 1 50 pF filter and the 
30 pF one. This makes it easy if you have 
large quantities of surplus dipped mica 
capacitors of odd values* 

The reduction in rf voltage is something 
like 50 dB, dropping from four volts down 
to about 1/100,000 of a volt. This is plenty 
for power and lead filters. The cost in parts 
is that of four capacitors at around 10 cents 
each J and a resistor for a coil form, 

"Bough ten" Feedthrough Capacitors 

The first ones tried were disappointing. 
The type **FT/' shown in Fig, 6, allowed 20 
mV to leak through. 

I did dig up a couple of good ones out 
of a 1946 surplus UHF Navy unit. I 
suspect that the price will be quite high on 
such units, if they can be found. These 



..n □ 



Fig. 6. Type *TT" feedthrough capaciton 



HEAVY l/B m. PIN 





CUPPED 



Ef«D vriw 



Fig, 7. Feedthrough capacitor. 



38 



73 MAGAZINE 



What's All the Shouting About 



9 




It's the All New C^^ FM-DX 

Amateur Net $589.95 — Factory Direct Only 

Owners are shouting their praise 

for all sorts of reasons 
The ones we hear most often ore , 

i 

• Tlie operating simplicity, accuracy and stability of the Synthesizer 
and LED Frequency Readout. 

• Tlie unmatched receiver performance with super sensitivity and 
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• Tliose beautiful, clean 35 Watts of Transmitter Output. 

• The rugged Modular construction. 

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In Pa. call (717) 299-7221 (collect) 



AUGUST 1975 



39 



look like Fig» 7, and perhaps some reader 
from the sales department of Sprague or 

Centralab or Erie can tell me what they 
are, and for how much they go to amateurs 
interested in good UHF feed through by- 
passes. They do seem to work as well as the 
final form shown in Fig. 5, so if you can find 
them, pay the price, and have a wall to put 
them in, such as in an enclosed if stage, you 
can use them. 



SubminiatUFe Filters 

The test setup of Fig, 1 being in opera- 
tion^ a smaller version was tried, to be ready 
for the size reduction being looked forward 
to with aU kinds of new and exciting very 
small conponents becoming available on the 
market. 

As long as 30 pF capacitors worked well, 
anything over that would naturally be all 
riglit, so with a 1/10 Watt resistor for the 
choke coO form, away we went. 

While this is not as small as can be made 
today, when you get into chips and hybrids, 
prices go in an inverse ratio. Little 1/8 inch 
by 1/8 inch by 1/16 inch square Lafayette 
ceramics cost around 13 cents, so we still 
can call this one low cost. 

The assembly is just the same as in Fig, 5, 
with the total space occupied being 1/2 inch 
long by 5/8 inch wide by 1/4 inch high, and^ 
as mentioned, it could be cut down even 
more if you tried. 

It worked just the same as the larger one 
in Fig. 5. Need I say more? 



fi VOLTS 



+0- 



6- 



B 



A 
B 
C 

D 

E 

p 



.5 V 
,02 V 
,02 V 
I V 
.03 V 
,02 V 



e VOLTS 



+0 



%- 




ft 



RF FBOMv 

EXCITER -^ 



nr AMPLIFIER 



-^ RF OUTPUT 





Fig, 8. Test remits, rf on batteries and leads. 



Fig. 9. Battery lead filters. 

Checking Out the Filter 

Fig, 8 shows the results of tests con- 
ducted on a crystal-controlled exciter and rf 
final destined for use in the 432er Solid 
State assembly. Note the one volt of rf at 
test point D without the filter. At the same 
point, also without the filter, about a tenth 
of a volt was found with only the exciter 
fired up. See Fig, 9, You can see what that 
kind of rf path will do for feedback from a 
quarter Watt or a 1/2 Watt final. 

So a piece of copper-clad was put down 
under the two units as shown in Fig, 9 and 
the two filters instaned. Perfect! No rf could 
be detected at all at any place on the 
batteries- Note that two filters are now 
present across any feedback path through 
the batteries and their leads- 
There still exist possible voltage field and 
magnetic field feedback paths between the rf 
final and the exciter, but that*s another 
story. The battery lead feedback path is now 
eliminated. And at least one thing shows up 
in favor for the solid state devices. There is 
only one wire in which to put a filter! 



40 



73 MAGAZINE 



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Elliott S. Kanter W9KXJ 
3242 W. Hollywood 
Chicago IL 60659 



Surveying the DVM Scene 



DO you remember when a single CK-722 
cost five dollars, or for that matter 
when one decade counter cost about ten? If 
you, like most of us, can remember those 
prices and what they are today, you can 
appreciate the growth and acceptance of the 
digital vom, or DMM. 

Digital multimeters as opposed to conven- 
tional analog-mete red devices offered several 
distinct advantages and until recently, one 
disadvantage. On the "plus" side of the 
ledger: accuracy, simplicity and lack of 
parallax. On the ''minus'* side, cost fre- 
quently in the range of about four hundred 
dollars* 

Why should a digital meter cost so much 
more than a conventional meter, or more 
accurately, why did it cost so much more? 
Until recently, costs of digital display 
devices priced the DMM out of the reach of 
hams and confined it to the R&D laboratory 
bench. However, with the pocket calculator 
boom, the cost per digit of display dropped 
dramatically from around ten -do liars per 
digit to around a dollar a digit 

If we were to attribute one singular 
advantage to the DMM over the analog meter 
It would be simplicity. Due to different 
viewing angles it is possible to get several 
values from a given analog meter reading 
(that is, assuming the meter hasn't been 
dropped or driven off-scale and pegged). 
This duplicity is known as parallax. How- 
ever, with the digital display, we deal with 
absolutes. For example, "125", regardless of 
what angle we view these three digits, will 
read "125". 

Terms 

Digital meters use a set or two of terms 
unique to themselves, and it behooves the 
smart shopper to understand them and that 
to which they refer (usually some magnitude 
of $$ over the competition). 



Accuracy, as: ± 2% ±1 Digit — The 
reading (basic) will be accurate to within ± 
2% ± the least significant digit, e-g- E in = 
100 V ± 2% - displayed as 98 or 102, ± 1 
digits Readout 103- -101 Or 99-97. 

Display, as: SVi Digit — For reasons of 
economy, the most significant digit wi 
display either or 1 , so: 

TA Digit displays - 199 Max 
SVi Digit displays - 1999 Max 
41/2 Digit displays- 19999 Max 

BUT 
4 Digit displays - 9999 Max 

Auto-polarity: Voltage and current wi 
be displayed with the proper polarity prefix 
automatically, without the need to reverse 
leads or flip switches. 

Auto-ranging: Automatic display of 
voltage and current within the capabilities of 
the device with no need to utilize a ran^ 
switch. 

Selecting A DMM 

Buying your first DMM is alot like buying 
a car, stereo or for that matter, taking a 
mistress. Obviously you get what you pay 
for. Are you going to use this unit only on 
your bench, or will you be climbing towers 
with it? If you can be satisfied to be 
bench-bound you can get a model with ac 
only operation. If you choose to '*fly" select 
one with capability for dc as well as ac 
operation. How many digits are enough? 
How accurate do you want to be, keeping in 
mind that most voltage and resistance 
measurements on schematics were taken by 
a trusty, oft-dropped 20kl2/volt VOM, Do 
you want to read current to the pi co- 
Amperes? 

Many people feel that It's cheaper to 
build than to buy; with today's market place 



42 



"7^ MAflA'ZIMC 



that remains to be seen. The lowest priced 
DMM fully assembled, calibrated, etc, is 
$170-00 as opposed to the least expensive 
kit DMM at $79,00, but for that extra few 
bucks you lose an extra % digit and get full 
calibration and the ability to meter current. 
The choice is yours, but remember^ your 
meter will only be as accurate as your 
calibration sources. 



Survey 

The following survey/buyer's guide repre- 
sents major and minor manufacturers of 
DMM devices. Prices listed are current, but 
the reader should beware of Murphy's Law 
Sub-Section XfVa, which states, '*. . Jf a 
price can go up, it will most assuredly and 
following closely the publication of a 
buyer's guide. . /', 











Power 


Digits 


Manufacturer 


Model 


Price 


Wired/Kit 


Source 


Displayed 


Batlantine 


3/24 


1 95.00 


W 


DC/ AC* 


3 


B-K Precision 


281 


1 70.00 


W 


AC 


2% 


B-K Precision 


282 


200.00 


w 


AC 


2% 


Dana Meter 


2000 


195.00 


w 


DC 


Z% 


Data Precision 


134 


189.00 


w 


AC 


372 




245 


295.00 


w 


AC/ DC 


4'/2 


Data Technol. 


21 


269.00 


w 


DC/ AC* 


314 


Digi Tec 


2110 


219.00 


w 


AC/DC 


3% 




2120 


275.00 


w 


AC/DC 


37^ 


Fluke 


8000A 


299.00 


w 


AC 


3% 


Heath 


1 M-1 202 


79.95 


K 


AC 


2/a 




IM-102 


239.95 


K 


AC 


3% 


Hewlett-Packard 


9 70 A 


275.00 


w 


DC/AC 


372 


Hickok 


334 


229.00 


w 


AC 


372 


Keithly 


168 


299.00 


w 


AC 


372 




168 


359.00 


w 


AC/DC 


3'/^ 


Non-Linear Sys 


LM-4 


187.00 


w 


AC 


4 


Simpson 


360 


295.00 


w 


AC/ DC 


3%+ Analog Mtr 


Tekelec 


357 


179.00 


w 


AC 


3% 


Weston 


4448 under 300.00 


w 


AC 


3% 




4449 " 


** 


w 


AC 


3% 




4440 " 


ft 


w 


DC 


3'A 




4442 " 


ft 


w 


DC 


372 




4443 " 


»» 


w 


DC 


3% 




Legend: 








, 






(*} Optional lAddltional Cost tern) 


1 

1 






DC - Battery operation 




S 



DVM Manufacturers & Addresses 

Ballantine Laboratories, P.O. Box 97, Boonton NJ 07005 

B-K, Div Dynascan, 1801 Bell Plaine, Chicago I L 60613 

Dana Laboratories, 2401 Campus Dr., Irvine CA 92664 

Data Precision Corp., Audubon Rd., Wakefield MA 01880 

Data Technology, 2700 Fairview, Santa Ana CA 92704 

DiglTec, 918 Woodley Rd., Dayton OH 45403 

John Fluke Co., P.O. Box 7428, Seattle WA 981 13 

Heath Co., Benton Harbor Ml 49022 

Hewlett-Packard Co., 1501 Page Mill Rd., Palo Alto CA 94304 

Hickok Elec. Instr. Co., 10514 Dupont Ave., Cleveland OH 44108 

Keithly Instrument Co., 28775 Aurora Rd., Cleveland OH 44139 

Non-Linear Sys., P.O. Box N, Del Mar CA 92014 

Simpson Electric Co., 853 Dundee, Elgin IL 60120 

Tekelec Inc., 31829 La Tienda Dr., Westlake Village CA 91361 

Weston Instruments, 614 Frelinghuysen, Newark NJ 07114 



W9KXJ 



AUGUST 1975 



43 




. . .the 5 band Atlas-210 solid state SSB 
transceiver for 10, 15, 20, 40 and 80 meters 

. . . and the Atlas-215 for 15, 20, 40, 80 
and 160 meters 

The same outstanding perfornnance, reliability, and compact size as the Atlas-180 • . . Only 372 in, 
high, 972 in. wide, 972 in, overall depth, and only 7 lbs. total weight , , . Operates directly from 12- 
14 volts D.C. All solid state, modular construction . . . No transmitter tuning (special Braille dial 
available for blind operators at no extra cost), 

FREQUENCY RANGES, Atlas-21 0:3700-4050, 7000- 
7350. 14,000-1 4.350, 21,100-21,450, and 28,400- 
29,100 KHz, Model 215 deletes 28,400-29,100 band, 
and instead covers 1800-2000 KHz. 
POWER RATING: 200 watts P,E,P, input and CW 
input. *0n 10 meters the power rating is 120 watts* 
PLUG'IN DESIGN, for quick removal from mobile 
mounting, and insertion into AC Console as illustrated* 

PRICE; Model 210 or 215».S599 • AC console, 117 V 50*60 cycles-^129 

• AC console, 117 230V „, $139 • Mobile plug-in kit. ..$44 




IP 



...and the best place 
to buy Atlas 
...Henry Radio, 
naturally 



Why buy from Henry Radio? 

Over 40 years experience. No finance charges if paid 
within 90 days. Low interest contracts - 8%/yr add 
on (14% annua/ rate} - as long as 24 months. 10% 
down or trade-in down payments. Good used equip- 
ment Mosf makes and modefs. Used equipment car- 
ries a 15 -day trial, BO-day warranty and may be 
traded bacfc within 90 days for full credit towards 
the purchase of NEW equipment Write for literature. 
Export inquiries invited. 



11240 W. Olympic Blvd., Los Angeles, Calif. 90064 

213/477-6701 
931 N. Euclid, Anaheim, Calif. 92801 714/772-9200 
Butler. Missouri 64730 816/679-3127 



Henry Radio is 
Exclusive Export 
Agent For 
Atlas Radio Inc. 



M 



Ptirtif fithiar* *^ rtian/»i 



,tU, 



Ralph E. Taggart WB8DQT 
4515 Oakwood Drive 
Okemos MI 48864 



Ho^v About a 
Weather Satellite Monitor? 



In a serfes of previous articles in 73 (Sept 
74, Dec, 74, and June 75), I outlined a 
number of circuits and techniques that could 
be used to display weather satellite pictures 
on conventional SSTV monitors. My corres- 
pondence in regard to these articles indicates 
that there is a widespread interest in copying 
weather satellite pictures and, as one might 
expect, the interest is not confined to 



individuals who are active in SSTV. The 
volume of mail clearly indicated the desira- 
bility of a simple monitor circuit designed 
specifically for weather satellite service, and 
this article will describe such a project 

The circuit is simple, yet incorporates 
some of the latest circuit ideas which 1 have 
developed in experimenting with this 
interesting mode. In addition, printed circuit 




470 



24 00 Hi PLL 



i2V 



-J MYLAR 



♦12 V 



lOK 
VIDEO 




ViOfO AMP 



*,Q05 
OfSC 



CRT 



I WATT 

AUDIO 

AMP 



-I2V 

240OHI 
ACnVE FILTER 



^r [ 




IO'20K 



•O-t mA 

AJUC 1 



-lav 



RS 



Fig. I. Unless noted, all resistors are 1/4 or 1/2 Watt, 10%. Capacitors are mylars disc, or electrolytic 
(polarity marked) as noted Unmarked diodes are general purpose computer or switching types 
(1N457, 1N914, etc.). Rl - 5k pc pot, VCO frequency controi SI - DPDT toggle, receive (R) or 
display (D). S2 — normally closed push-button^ phasing, S3 —4 pole 2 pos. rotary^ APT/DRIR mode 
selection. Components marked with an asterisk f*) mount on the chassis, ail others are on board #1, 
ICl - 7400, IC2 - NE565 PLL, IC3, 4, 5, 6, 7 - 7490, IC8 - 7492, 1C9- 741 op amp. Tl - output 
transformer, 10^20k to 8 Ohms. Rs — 50 Ohm pot, adjustable meter shunt (see text). J — RCA phono 
jack; Jl — 2400 Hz to left charmel input of tape deck^ J2 — to left channel output of tape deck, JZ — 
satellite video from right channel output of tape deck^ Ql — HEP712. 



At tnt icx 1Q7(=; 



45 




TQTP\ 

Fig, Z. Deflection circuit (board #2), General component notes as in Fig. 1, Q2 ~ HEP55, Q3, 5 — 
HEP 245, Q4, 6 - HEP 247. ICll, 12 - 741 op amp. Yl - horizontal deflection coils, Y2 - vertical 
deflection coils; both coils incorporated in standard TV deflection yoke (Stancor DY-2A orequiv,). SS 
— see Fig. 1, R2- Im DRIR hor, size. R3 - Im APThor. size. R4 - Im DRIR vertical size, R5 — Im 
APT vertical size* S4 — SPST toggle, close to reset vertical sweep, open to run. Components with an 
asterisk f*J mount off the boards all others mount on board #2. 

board layouts were developed for the active 
circuits and are included here to make the 
project even easier to tackle. Virtually all of 
the circuit components, v^jth the exception 
of switches, controls^ and power supply, 
mount on two small circuit boards, per- 
mitting complete flexibility in packagng the 
final unit. In the course of development^ the 
original circuits were modularized into a 
number of units that interface with my own 
station, which uses a variety of CRT and 
facsimile techniques, but the same boards 
can be incorporated into an extremely com- 
pact CRT monitor for multi-mode weather 
satellite display. Multi-mode capability is 
required, since some satellites use the older 
APT picture transmission system (the polar 
orbiting ESS A 8 and the geosynchronous 
ATS satellites) while the current NOAA 
satellites utilize the time multiplexed DRIR 
mode that permits simultaneous trans- 
mission of both visible light and IR picture 
data. 

The technical details of the video format 
of the two modes will not be covered here. 
Ideally, the sync system of the monitor 
should be independent of the condition of 
the satellite signal for maximum reliability. 
This is achieved by generating a 2400 Hz 
sync reference tone that is recorded simul- 
taneously with the satellite picture, requiring 
the use of a stereo tape deck. Any tape 
format (reel-to-reel, cassette, or 8 track 
cartridge) may be used with the system. In 
addition to the recorder, a VHF receiving 



system will be required to complete the 
satellite receiving station- A low noise FM 
receiver with a 1 5 kHz i-f and crystals for 
135,6 (ATS), 1373 (primary NOAA), and 
137.62 (ESSA 8 and backup NOAA) will 
put you in business. 

Circuit Description 

The basic functions provided by the 
monitor circuit are listed below: 

1) During reception of a satellite signal, 
generation of a crystal controlled 2400 Hz 
reference signal which is recorded on the left 
channel of the tape deck while the satellite 
signal is recorded on the right channel. This 
tone serves as the sync reference signal 
during picture display. 

2) Video filtering and amplification of 
the satellite signal, and Z axis modulation of 
the monitor CRT, 

3) Switch selection of either the APT or 
DRIR display modes with appropriate sync 
count-downs and pre-set size and centering 
for both modes. 

Conceptually and physically the monitor 
is broken down into four sub-assemblies: 

1) Video and sync processing — board #1, 

2) Deflection circuits — board #2. 

3) The CRT and associated controls. 

4) The power supply. 

Video and Sync Processing (Fig, 1 ) 

These circuit elements are included on 
board #1 and control the generation of the 
2400 Hz reference tone, appropriate division 
circuits to generate either 4 Hz (APT) or 1 .6 



46 



73 MAGAZINE 



Hz (DRIR) trigger pulses for horizontal 
triggering, and satellite video filtering with 
additional amplification provided by a small 
transistorized amplifier module. In order to 
limit circuit complexity, several of the 
devices on board #1 are used for both 
receive and display functions, SI is used to 
set either of these tv^o conditions. In the 
receive mode only board #1 is operational, 

to reduce power consumption. With SI in 
the receive position^ I CI functions as a 2.4 
MHz oscillator whose output is divided by 
1000 (IC3, 4 and 5) to provide the 2400 Hz 
reference tone at Jl. This tone is recorded 
on the left channel of the station recorder as 
the satellite signal is recorded on the right 
channel. 

With SI in the display position all of the 
monitor circuits are functional. The 
reference tone recorded on the left channel 
is routed to J 2 where it locks up IC2, which 
functions as a 2400 Hz phase locked loop, 
tracking any small variations in the reference 
signal due to recorder speed variations. S2 in 
the input circuit to IC2 functions to unlock 
the PLL for picture phasing. The 2400 Hz 
output of the PLL is routed through SI to a 
series of digital frequency dividers* The 



-303V 



390 K iOOK 




Modular units used to develop the satellite 
monitor. The large chassis contains the CRT^ 
deflection yoke, and the HV module. The 
cabinet with the meter contains the two 
drcuit hoards and the power supplies. If the 
unit were constructed in a single cabinet it 
would be possible to package it in a cabinet 
about the same size as that for the elec- 
tronics package. Such as integrated unit 
should have the power supply located 
rBmotely to eliminate 60 Hz trace distortion 
in the CRT. 



VIDEO 
INPUT 




500K 
FOCUS 



300V 



* 5 TO 7KV 



Fig. 3. CRT and associated control circuits. Fixed 
resistors are 1/2 Watt, brightness and focus pots are 
2 Watt compo^tion pots, 

division sequence is controlled by two sets 
of contacts of the mode switch (S3). In the 
APT mode the 2400 Hz signal is divided by 
600 (IC3, 4 and 6) to produce a 4 Hz square 
wave. In the DRIR mode the 2400 Hz is 
divided by 1 500 (IC3, 4, 7 and Yi of IC8) to 
produce a 1 .6 Hz square wave* The appro- 
priate square wave output of the division 
sequence is routed to a 5 ms single shot (IC 
9) which provides a short TTL pulse to 
trigger the horizontal deflection. This trigger 
pulse is routed to TPl and also to the base 
of Ql, where it provides for retrace blanking 
of the video signal. Since the DRIR video 
format consists of alternate lines of visible 
and IR picture data, it is necessary to blank 
alternate lines of video in the DRIR mode to 
assure display of either visible light or 
infrared (IR) pictures. This is accomplished 
by routing the trigger pulse to Vi of IC8^ 
which functions as a flip-flop, turning on the 
blanking transistor (Ql) on every other 
video line. 

Video processing is straightforward yet 
effective. The satellite video from the right 
channel of the tape deck is routed to J 3 and 
through a 2400 Hz active bandpass filter. 
This filter has a bandwidth of 1000 Hz and 
unity gain. A sharper filter would reduce 
noise in the IR channel {video bandwidth of 
450 Hz) but would degrade resolution in the 
visible channel (bandwidth of 900 Hz). 
Further video amplification is provided by a 
small transistorized amplifier available from 
Radio Shack. Any small 1 Watt amplifier 
would do equally welL A meter with an 
adjustable shunt^ in the power lead to this 
amplifier, serves as a video level indicator. 
The output of the amplifier drives Tl, which 



A I ij^ I I r*' 



^ f\-rtz 



47 



boosts the signal to a voltage sufficient to 
drive the CRT grid. The blanking transistor 
(Q1) shorts out the video for the duration of 
the trigger pulse in either the APT or DRIR 
modes and on alternate lines in the DRIR 
mode to provide retrace and alternate line 
blariking. 

Deflection Circuits (Fig. 2) 

The deflection circuits are an adaptation 
of widely used SSTV deflection circuits and 
provide highly reliable performance. The 
horizontal trigger pulse from TPl of board 
#1 turns on Q2 for the duration of the 
pulse, shorting out the 3 mF horizontal 
discharge capacitor. When Q2 goes off at the 
end of the trigger pulse, the 3 mF capacitor 
begins to charge thFOUgh either the APT or 
DRIR size controls, depending upon the 
setting of the mode switch (S3). This voltage 
ramp drives an operational amplifier (ICl 1) 
which in turn drives a pair of complimentary 
power transistors (03 and 4) with the 
horizontal deflection yoke in their common 
emitter circuit. Centering of the horizontal 
trace is accomplished by feeding a variable 



voltage into the non-inverling input of the 
op amp. A single setting of the centering 
control is used for both the APT and DRIR 
modes. 

The vertical deflection system operates in 
a similar manner except for the time con- 
stants of the discharge circuit and the fact 
that the vertical deflection system is cycled 
manually with a switch rather than a tran- 
sistor. The 2000 mF vertical discharge 
capacitor is shorted out by S4 to initiate the 
vertical sweep. When S4 is opened the 
capacitor begins to charge through either the 
APT or DRI R size control The ramp voltage 
drives another op amp (1C12), which in turn 
drives the deflection transistors (Q5 and 6). 
The centering system for the vertical deflec- 
tion is identical to that used in the hori- 
zontal circuit, 

CRT Control Circuits (Fig. 3) 

The 5AHP7A CRT is operated in a 
grounded cathode mode with the video 
signa! applied to the grid. Adjustable grid 
bias is supplied by the brightness control to 
set the trace so that it is just below the 



» +300 



» -30O 




•-^SKV 



♦I2V> 




lOK 



**5V 



OHEP245 
c- 



r2V 



• + I2V 



-J- [000^ F 
15V 

m 



LM320-iav 



T 



-I2V 



(OOO^F 

♦Trsv 



II5VAC 



¥\q. 4. ¥oweT Supply. All unmarked diodes are HEP 1 70, Tl - Stancor PC- 8401 (470 Vet 40 mA, 6.3 
V 1 A), T2 - Stancor P8357 (24 V 2 A). T3 - Stancor HO-409 Hyback. The power switch can be 
located on the monitor brightness control to control the supply. Suggested: Cinch Jones P-310-AB 
plug on nnonitor chassis, S-SIO-CCT on power cable; 1-ground, 2-6.3 Vac, 3-+5 V, 4--f-12 V, 5- 12 V, 
6- ^300 V, 7' '300 V, 8- line from SIB, 9- common ac, 10- smtched ac, Kl - 3PDT 24 V ac relay 
controlled by SI (receive /display) on monitor; only the +5 V circuits are operational in the receive 
position while the entity monitor functior^ in the display setting. 



48 



M A A /^ A 




Fjg. 5(aX PC board #1 (full size). 



visibility threshold in the absence of video. 
The component values in the brightness 
circuit are chosen so that the video output 
from T1 is not loaded excessively by the grid 
circuit- The 5AHP7A is electrostatically 
focused, as indicated in the schematic. The 
5FP7, v^hich is commonly available on the 
surplus market, may be used with two 
modifications. The focus pot may be elim- 
inated but either a permanent magnet or 
electromagnetic focus coil must be used. The 



ong persistance of the P7 phosphor enables 
many details of cloud cover to be evaluated 
as the image Is being photographed. With 
some modification of circuit values and pin 
connections a number of the small P4 tubes 
used in solid state TV circuits could also be 
used, but they would not have the long 
persistence feature. Since detailed evafuation 
of cfoud and terrain features is best accom- 
plished with photographs of the CRT image, 
this is not a great drawback — and a great 



Fail size negatives for Fig, 5(a) are available for $2,00 each from PC NEGS. 73, Peterborough NH 03458. 

Order 4rWB8DQT- 1 , aq 



A I ijn-t I 



^ tv' 




RIGHT NOW 



is the time to order your 




Don't wait until 197S f$ half over. Get 
your new Callbooks now and have a full 
year of the most up*to*date QSL informa- 
tion available anywhere* 

The new 1975 U, S. Callbook will have 
over 300,000 W & K listings. It will have 
caHs, license classes, names and addresses 
plus the many valuable back-up charts and 
references you have come to expect from 
the CallbooK. 

Specfalize In DX7 Then you're looking for 
the new, larger than ever 1975 Foreign Call* 

book with over 225,000 calls, names and 
addresses of amateurs outside of the USA. 



United StalM 
Callbook 

All W & K Ustings 

$12.95 




Foreign Radio 
Amateur Calibook 
DX Ustings 

$11.95 



Order from your favorite electronics deal- 
er or direct from the publisher. All direct 
orders add 75^ shipping and handlfng per 
Callbook. 



BROCWV 



f OR RADIO AMATEUR III 



£SK 




k 



INC 

Dept B 925 Sherwood Driw 
Lake Bluff, III. 60044 




Fig. 5(bJ. Parts layout tor board ifl. 



many of the smalt 
reasonably priced. 



TV tubes are quite 






Power Supply (Fig. 4) 

The power supply is strictly conventional 
and any variations that v^^ould provide the 
proper voltages and regulation would work 
well. The HV module for the CRT is a 
simple transistor osciilator working into an 
unmodified TV flyback transformer. The 
basic supply should be re mo ted from the 
monitor to prevent 60 Hz distortion of the 
trace, but the HV module should be 
mounted close to the CRT so the HV 
connector from the flyback (which includes 
the HV rectifier assembly) can reach the 
appropriate connection to the shell of the 
tube. 

Construction 

Fig. 5 shows the printed circuit foil 
pattern and component layout for board #1 
while Fig. 6 provides similar data for board 
#2. If the component placement figures are 
followed carefully no problems should be 
encountered. Packaging of the completed 
boards with the CRT can be accomplished in 
virtually any enclosure that will hold them. 
The following controls and indicators are 



50 



71 IUiA./^A7IM 



TUFTS 



^adio Electronics 



386 Main St., Medford, Mass. 02155 



'TEA TURING VHF ENGINEERING 



// 



THE WORLD'S MOST COMPLETE LINE 

OF 
VHF— FM KITS AND EQUIPMENT 



CD1 Kit 
CD2 Kit 
C0R2 
SC2 Kit 
TX 144 Kit 
TX220 Kit 
TX432 Kit 
RX144/220FKit 
RX144/220CKit 
RX432 C Kit 
HT144BKit 
PA1501HKit 
PA2501HKit 
PA144/15Kit 
PA1 44/25 Kit 
PA220/15 Kit 
PA432/1 
PA40tOH Kit 
PA1 10/10 
PA1 10/30 
PS3 Kit 
PS12CKit 
PS24C Kit 
RPT144 
RPT220 
RPT432 



10 channel receive xtal deck w/diode switching 

10 channel xmit xtal deck w/switch and trimmers 

complete COR with 3 second and 3 minute timers 

10 channel auto-scan adapter for RX 

exciter — 1 watt — 2 meters » 

exciter— 1 watt— 220 MHz 

exciter— NEW-432 MHz 

140-170 or 210-240 MHz rcvr w/8 pole cer 455 filter 

140-170 or 210-240 MHz rcvr w/2 pole 10.7 xtal filter 

NEW-432 MHz receiver 

2 meter— 2w — 4 channel— hand held xcvr 

2 meter pwr amp— 15w— compl. kit w/SS switching 

similar to above — 24w 

similar to PA1501H less case, connectors and switching 

similar to above— 25w 

similar to PA144/15 for 220 MHz 

NEW— similar to PA144/15 except lOw and 432 MHz 

lOw in— 40w out— relay switching 

lOw in— llOw out 2 meter amp factory wired 

30w in — llOwout 2 meter amp factory wired 

power supply regulator card 

12 amp— 12 volt regulated power supply w/case 

24 amp — 12 volt regulated power supply w/case 

NEW— 15 watt — 2 meter repeater factory wired 

NEW— 15 watt— 220 MHz repeater factory wired 

NEW— 10 watt— 432 MHz repeater 

Repeaters are available in kit form — write for prices 



$ 6.95 

$14.95 

$19.95 

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$29.95 

$29.95 

coming soon 

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$595.95 

coming soon 



ITEM 


PART# 


DESCR PTION 




PR CE 


EXTENSION 






















































■ 


NAMF 

AnnRFRR 

CITY 

RTATF 


7IP 


TOTAI 
RH PPINfi 


TOTAI FNir^i nsFn 











operational controls and should be mounted 
where they are accessible: SI (receive/ 
display), 52 (phasing), S3 (APT/DRIR mode 
selector), S4 (vertical sweep), brightness, the 
video gain control, and Ml (video level). The 
focus control and deflection size controls are 
''set and forget'* features and can be located 
anywhere. Although not required, the use of 
IC sockets for the circuit boards is highly 
recommended as removal of a bad IC can be 
a chore if it is soldered directly to the circuit 
board, J 1-3 can be mounted on the rear 
apron of the completed unit. The photo 
shows the modular packaging used for my 
own circuit evaluation. Except for the large 
meter used for the video level control, the 
whole unit could have been packaged in the 
cabinet used for the electronics package, had 
that been the initial goal while the circuits 
were being designed* 
Initial Setup 

Prior to connecting the power supply to 
the completed unit you should verify the 
presence of the proper voltages and polarity 
— a mistake here will send you back to the 
parts store for additional ICs and transistors! 



Place SI in the receive position and apply 
power. Attach a frequency counter to the 
common lug of SI A and adjust the 50 pF 
trimmer on board #1 for a frequency read- 
ing of exactly 2,4 MHz. This frequency 
should be set to the maximum resolution of 
the counter. Move the counter to pin 11 of 
IC5 — it should read exactly 2400 Hz. Move 
the counter to pin 3 or 8 of 1C6 - a reading 
of 4000 Hz should be obtained- Set the 
counter on pin 9 of ICS and you should get 
a reading of 1600 Hz, If you've gotten this 
far you can rest assured that the oscillator 
and all frequency dividers are operating 
properly. 

Set the counter on pin 4 or 5 of !C2 
With no input at J 2, adjust Rl for a 
frequency of 2350 Hz, Temporarily connect 
a test lead from Jl to J 2, The counter 
should read 2400 Hz, dropping to 2350 Hz 
when S2 is depressed and rising back to 
2400 when S2 is released. Remove the test 
jumper and turn off the monitor supply. 

At this point it is desirable to have a 
satellite tape for further tests^ The satellite 
video should be recorded on the right 




We make our SkyClaw™ vertical 
antennas for the ham who doesn't want 
to be a jack-of-al! bands. Because no 
antenna can be all things to all people. 
You tune our SkyClaw™ to your choice 
of 160 (50kHz bandwidth]. 80 (200kH2 
bandwidth), or 40 (the v^/hole band]. We 
don't fudge the tuning for multi-band 
performance. We put the materials into 
itthatletyou pump the legal limit through 
it We build it to withstand more wind than 
you'll find in a QSO on 75. 

And we deliver the whole thing for 
$79.50- postpaid in the USA. Radial and 
phasing harness kits are available, too. 

Ifs self-supporting. Weatherproof You 
put it up yourself with just 4 tools It stands 



247r And you connect to an SO -239 in 

its base- 
Now, then, Have you decided which 

kind of operator you want to be? 
Yes, Master 

DerSfori- 

Radio Co., Inc. 

2100 Enterprise Parkway 
Twinsburg, Ohio 44087 
(216) 425-8073 





52 



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53 



channel. Set the VU or recording level meter 
for the maximum permissible recording level 
on receiver noise with no signal present so 
you v^ill not overload the recorder with the 
actual satellite signal. ]1 should be con- 
nected to the left channel input of the 
recorder. When a satellite signal is heard, 
verify that SI is still in the receive position 
and apply power to the unit. Set the left 
channel recorder level for 1/3 to 1/2 of the 
permissible recording level on the 2400 Hz 
tone, and record the pass. 

During playback of the picture the right 
channel output of the recorder should go to 
13 while the left channel output goes to J 2. 
Set the output level of the tape deck to near 
maximum on both channels. If you are using 
a recorder rather than a deck, insert pads to 
keep the levels to J 2 and 3 at about 1 volt. 
Prior to applying power to the monitor 
preset all controls as follows: SI — display, 
S2 — normally closed, S3 — APT, S4 - 
closed, video gain — minimum, Ml shunt — 
zero resistance, all centering and size con- 
trols — midrange, brightness ^ minimum 
{maximum negative voltage on CRT grid), 
focus — midrange. Apply power to the 
monitor. After a few minutes for warmup, 
carefully advance the brightness control 
until the trace is just visible on the CRT — it 
should be a horizontal line* If no tine is 
visible, adjust both horizontal and vertical 
centering to bring it into view. Mask off the 
largest possible square viewing area on the 
CRT. Adjust the horizontal centering and 
APT horizontal size so the line just fills the 
viewing area from side to side. Momentarily 
short the collector of Q2 to ground — the 
trace should form a spot off on the left hand 
side of the screen. If the trace jumps to the 
right, turn the unit off and reverse the 
horizontal deflection leads and repeat the 
size and centering adjustments after reapply- 
ing power. Open S4 and observe the direc* 
tion of movement of the horizontal line. If 
the line moves downward close S4and move 
ahead in the adjustment sequence. If the 
trace moves upward, power down, reverse 
the vertical deflection leads, and reapply 
power. Set the vertical centering so the trace 
is just at the top of the viewing area with S4 
closed. Open S4 and set the vertical APT size 
control for a 200 second top to bottom 




Fig. 6(a) PC board #2 ffuH size), 

sweep. Switch S3 to the DRIR position and 
adjust the DRIR horizontal size control for a 
sweep that extends just beyond the margins 
of the viewing area. Cycle S4 and set the 
DRIR vertical size pot for a 7 minute top to 
bottom sweep- This should be done carefully 
so the pictures will have the proper aspect 
ratio. 

If all has gone well to this point you are 
ready to watch pictures. Back down the 
brightness control until the trace just dis- 
appears in a dark room. Play the previously 



Full size nega lives for Fig^ 6 (a) are available for $2,00 each from PC NEGS, 73, Peterborough NH 03458, 

Order =riWB8DQT-2. 



54 



73 MAGAZINE 




Fig, 6(b), Parts layout for board #2, 



recorded satellite tape into the monitor. If 
your recording is from ESSA 8 or one of the 
ATS satellites, set S3 to APT, If a NOAA 
satellite was copied, set S3 to DRIR. Slowly 
advance the video gain control until satellite 
video is visible on the CRT- A proper gain 
setting represents a point showing good 
whites while still retaining black areas in the 
picture. It is unlikely that the picture is 
properly phased at this point. In the case of 
an APT picture, improper phasing is indi- 
cated by the presence of a vertical white bar 



in the picture area (actually the satellite sync 
pulse). Press S2 until the bar moves to the 
left edge of the picture, and release. The 
APT picture is now properly phased. In 
normal operation S4 is kept closed during 
the inter-picture interval (steady 2400 Hz 
satellite subcarrier) and opened at the start 
of the picture- Phasing need only be Accom- 
plished once during a single pass or picture 
sequence, as long as the recorder is not 
turned off. DRIR phasing is used to deter- 
mine which of the pictures, either visible 
light or IR, you wish to view. The sync pulse 
of the DRIR format is a vertical white bar 
that is actually composed of seven discrete 
pulses which should be visible if you look 
closely. Phasing is accomplished by pushing 
S2 until the bar lines up just off the left 
margin of the vie wing area. In the IR format, 
the space just after the sync bar will be 
white while the visible channel view will 
have a black area immediately following the 
sync bar. If the picture, as phased, is the 
wrong channel (the one you don't want at 
the moment) simply keep S2 depressed and 
a second sync bar will drift in from the right 
and move to the left margin. When this one 
lines up with the left side of the viewing 
area, release S2 and you are in business with 
the proper video channel Both the visible 
and IR channel of the DRIR format will 
have usable video during daylight passes 
while the visible channel will be completely 
black at night with only the IR view 
producing usable pictures. As noted in the 
previous references, the NOAA DRIR 
format produces a continuous vertical strip 
of video rather than discrete frames. The 
geometry of the CRT means that only about 
seven minutes of this strip can be seen at one 
time. 

Once you are getting reasonable video 
display you can gradually increase the resis- 
tance of the 50 Ohm meter shunt pot. The 
shunt should be set at a point that gives near 
maximum meter deflection on video peaks. 
The meter can now be used for video levels. 

Photography of the weather satellite 
pictures can be done with virtually any 
camera that can be focused on the CRT. See 
the 73 SSTV Handbook for photographic 
techniques. All photographs should be made 
in a dark room because of the long time 



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exposures required. Polaroid type 107 film 
will give you ''instant'* weather satellite 
pictures but gets expensive if you plan to 
take pictures every day. 35nnm black and 
white film is convenient for taking large 
numbers of pictures but you are forced to 
wait until you fill up the roll unless you load 
your own film in short segments. The 
advantage of roll film over Polaroid (aside 
from cost) Is that the final pictures can be 
printed at any size desired. Despite the small 
size of the CRT, satellite pictures enlarged to 
8x10 inches look quite good. Most satellite 
buffs choose their film and camera on the 
basis of how many pictures they routinely 
acquire and the state of their wallets, 1 use 
35mm for day to day operation, keeping 
Polaroid in reserve for demonstrations. You 
will probably shoot a lot of Polaroid in the 
beginning and then phase into other film 
types as you get into the routine. 

I will be happy to correspond on the 
subject of the satellite monitor but please 
include an SASE so I have change enough to 
buy morefilml 

• . • WB8DQT 




Hurricane Carmen battering the coast of 
Yucatan in September, 1 974, The coast and 
interior of Mexico are faintly visible to the 
left while Cuba, outlined in sunglint off the 
waters of the Caribbean, may be seen in the 
upper right. This picture was transmitted 
from one of the operational NO A A satellites 
using the DRIR mode and can be displayed 
on the monitor. The NOAA sateUites 
transmit a continuous video signal and this 
segment represents just part of a long picture 
strip extending from southern Greenland in 
the north to Panama and western South 
America to the south. 











% 



i 





i 



Cridded NOAA data relayed by the ATS-3 
geostationary satellite on 135.6 MHz. Such 
data, from either ATS-1 or ATS- 2, as well as 
the pictures from the polar orbiting ESSA-S, 
are transmitted in the APT mode and can be 
dmplayed on the satellite monitor. 



56 



-3*5 AJIA i^A "^IMI- 




IF YOU'RE STILL SETTLING, WORRYING, 

FIDDLING, OR PUTTING UP 



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continuous average power. CHECK THE SPECS!) 

WORRYING THAT YOUR OLD LINEAR WON'T HANG TOGETHER through a long, tough 
contest weekend . . . or thirty minutes of "Key<lown" time on SSTV? Every ALPHA is 
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BROOKSVILLE, FLORIDA 33512 

(904) 596-37n 



AUGUST 1975 



57 



Gene Hinkle WA5KPG 
9503 GambeJ's Quail TYail 
Austin TX 78758 



The QRPAccu-Keyer 



The Accu-Keyer is a low-<;ost TTL inte- 
grated circuit keyer having many 
features comparable to those of many high- 
cost commercial keyers. These features 
include: self-completing dots and dashes, dot 
and dash memories, iambic operation, dot 
and dash insertion, and automatic character 
spacing/ The Accu-Keyer was first 
described in the August, 1973 issue of QST. 
However, that keyer used TTL circuits 
which are not compatible with QRP opera- 
tions. The QRP Accu-Keyer is a much 
needed alternative to the original design. 

The QRP Accu-Keyer uses an integrated 
circuit family known as CMOS, CMOS (also 
known as COS/MOS by RCA) was first 
introduced during the middle 60's as an 
extremely low power digital circuit using 
complementary-symmetry metal oxide semi- 
conductors. The basic CMOS circuit uses 
complementary, insulated gate FETs, to 
achieve extremely low standby power — 10 
nW per package for gates. This power feature 
and moderate cost makes CMOS an attrac- 
tive logic family to consider for QRP opera- 
tions, where power is at a premium. This is 
the philosophy behind the QRP Accu-Keyer. 

Design Concepts 

Several modifications must be made to 
the original Accu-Keyer logic in order to 
incorporate the CMOS family. The basic flip 
flop design in CMOS differs from that of 
TTL. The notable exceptions are the set and 
clear functions. The set and clear functions 
on a TTL flip flop are inverse logic com- 
pared to CMOS functions- CMOS circuits use 
a logic '*one'- as a set or reset signal and a 
logic ''zero" as a normal state. This is 
directly opposite to TTL where a normal 



Garrett, "The WB4VVF Accu-Keyer", QSZ 
August 1973, p. 19. 



State is high and a set/ctear command is low. 
Therefprei jt is clear that to convert a TTL 
logic diagram to a CMOS diagram, all sets 
and clears must be inverted, 

Another difference between the two 
families is that of supply voltage, TTL 
requires a rather critical supply source near 5 
volts in order to function properly. CMOS, 
on the other hand, will work properly with 
any supply voltage between 3 and 15 volts, 

and the supply regulation is non-critical. 
This means that the keyer will operate 
directly from the batteries which power the 
QRP rigj without any regulation needed. 
This is an excellent feature of CMOS over 
TTL, 

QRP Accu-Keyer Circuit 

Fig, 1 shows the schematic of the QRP 
Accu-Keyer* There are several differences 
between the QRP version and the original 
design. A CMOS astable clock was designed 
so that discrete components could be held to 
a minimum, IC8 is connected as a typical 
astable, producing a square wave output 
The output period is equivalent to one time 
unit in Morse code. Secondly^ since the 
keyer is used with a QRP rig, HW-7 in this 
instance, the output driver needs to be only 
a low level transistor switch. This greatly 
simplifies the output stage of the keyer. 
Driving a higher power rig would only 
require the inclusion of a suitable output 
transistor after QT Thirdly, as previously 
mentioned, all set/clear lines on the type 
'*D" flip flops must be inverted when using 
CMOS In the original circuit. 

Construction 

Only eight CMOS circuits are needed for 
this design. The ICs were mounted in sockets 
for ease of construction. The sockets were 



58 



73 MAGAZINE 



TIME CLOCK 
5-5CWPM 



22 K 



HW-? 
KEYED 




NOTE* 

ALL PINS E4 - +»2V 
ALL PINS 7' GROUND 



ICNO. 


TYPE 


1.2.6 
3.4.5 

a 

7 


40MAE 
40I3AE 
400IAE 
4023AE 



Fig, 1. Schematic diagram of the QRP Accu-Keyer using CMOS integrated circuits. Output transistor is 

sufficient to drive a HW-7 QRP transceiver. Standby power is Jess than a microwatt. 



first mounted on a perforated board and 
then hard-wired together with small solid 
hook-up wire. No special precautions are 
needed when working with CMOS, However, 



it is recommended that CMOS not be in the 
circuit when using a soldering iron with an 
ungrounded tip, CMOS are now presently 
being made with diode protected inputs, and 




Inside photograph of HW-7 with keyer board in place. Placement of the keyer hoard is 
non -critical inside of the HW-7. The associated conljols are mounted on the rear panels ^ 
as well as a tune button. Three conductor phone jack replaces the usual two conductor 
jack for the twin paddle key, (Photos courtesy of Robert Baker WA5KVB.) 



AUGUST 1975 



59 



p^ 



^■^v 



can usually withstand a limited amount of 
abuse, but why take a chance? Bypassing the 
CMOS supply is not necessary because of the 
excellent noise immunity inherent in the 
family. The excellent flexibility and ease of 
design make CMOS a very attractive family 
to work with. 

There may be some question as to the 
suppliers of CMOS. There are several surplus 
advertisers who list CMOS, Allied Elec- 
tronics and Burstein-Applebee also list 
CMOS in their current catalogues. Generally, 
the D flip flops are from $1 to $1,50, while 
the gates are all well below a dollar per 
package. Although the ICs appear to be 
more expensive than their TTL counterparts, 
the power supply requirements and ease of 
applications should be considered also. 
There are several nomenclature items which 
should be stated. The RCA's commercial 
version of CMOS (4000 series) is listed with 
the suffix AE, signifying supply voltage of 
3-15 volts and commercial specs respec- 
trvely. The AD suffix signifies 3-1 5 volts 
with military specs. The AE version is 
significantly less expensive than the AD 
version^ and is usually more plentiful on the 
surplus markets. The 4000 series is the most 
readily available type of CMOS now pro- 
duced. 

Since this keyer was designed to go with a 
QRP rig, a HW-7 was a likely candidate. The 
photo shows the installation of the keyer to 
the Heath kit* The keyer is mounted on a 




Inside view of the ''Siamese" twin paddle 
key. Two inexpensive straight keys are used, 
although higher quality keys could be substi- 
tuted. Box measures 4'' x 2'' 3/8" x 6" 

inches. 




Rear view of the control layout on the 

vector board and located in the rear side 
corner of the HW-7. The keyer is connected 
directly across the supply terminal since no 
regulation is necessary. The speed adjust- 
ment pot and auto-space switch are both 
mounted on the rear plate. A tune push- 
button is also included to facilitate the 
tune-up of the rig. Since a twin paddle is 
now needed instead of a straight key, a 3 
conductor earphone jack is installed where 
the previous jack was located. 

The twin paddle built makes use of two 
straight keys in a Siamese paddle configura- 
tion.^ Two inexpensive straight keys were 
bolted together and mounted perpendicular 
to the bottom of a smalt utility box. Two 
small paddles, made from a fiberglass PC 
board, were then connected to the two 
straight keys. If a better "feel" is needed, 
two higher grades of straight keys can be 
used. However, the original design is quite 
adequate- 

The QRP Accu- Keyer is definitely the 
answer to the power crisis when working 
QRP from a battery source. Extremely low 
standby power can be obtained by using the 
CMOS integrated circuits. This keyer can be 
used with any rig if the appropriate driver 
transistor is installed, I hope these sugges- 
tions will be helpful to those who work 
CW-QRP from a finite power source. 

Additionaf Reference 

COS/MOS Digital Integrated Circuits SSD-203A, 
RCA. 

,. ,WA5KPG 



Hex tor, "The Siamese Paddle", Hints and Kinks, 
Volume Six, p. 66, 



60 



73 MAGAZINE 



1 






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Electronics 



386 Main St., Medford, Mass. 02155 



AUGUST 1975 



61 



John M, Murray WIBNN 
4 Kenwood Circle 
Bloomfield CT 06002 



Catenary 

Suspense 



Take my advice: Don't use a hockey 
stick on your cat! Strang things are 
liable to happen. Aunt Henna was quite well 
adjusted for a cat until I began to use the 
stick. You see, she disagreed with me about 
the need for her to go out at night — and 
with glaring yellow eyes hid as far back as 
she could under any handy bed. Hooked 
with the hockey stick, however, there'd be a 
loud yowl; a scramble of flailing claws — as I 
chased her to the open door^ where she 
would leap into the snow, yelling her out- 
raged head off. 

For a short period the system seemed to 
be working quite well, I even tried to believe 
the message was getting across. Soon, I 
thought, she would go to the door by herself 
and meow plaintively, like a well-trained 
puppy. 

Aunt Henna had other ideas. For one 
things I noticed she suddenly had taken an 
avid interest in television. For hours she 
would stare at the boob tube, her eyes wide 
and unblinking. At the same time^ while 
watching, she was soon making strange 
sounds in her throat. Preference of pro- 
grams? She looked at 'em all - and even, we 
were astounded to note, learned how to turn 
the set on and off, but mostly on. 

And so things continued most of last 
winter, hockey stick routine included. She 
definitely didn't want to go out — and 
adroitly evaded me a good part of the time, 
dashing back to her beloved TV, 

One evening in May my hockey stick 



must have clipped her a bit, instead of 
scooping. 

''You bastards,** she spat 

'Took here, Aunt Henna," 1 said, ''no use 
including the family. This is all my idea- 
Make that single/' 

''Hurry down to Railroad Salva^ and 
save, save, save, brother," she hissed. 

Then it dawned on me that Aunt Henna 
had cussed me out. Perhaps I was cracking 
up- My XYL, Amie, was standing in the 
doorway, a twisty smile on her map. *M 
heard you talking to someone in here. 
What's going on?'' she demanded. 

*'Aunt Henna called me a bastards. I was 
merely trying to correct her grammar,'' 

Amie turned on her heeL "Tm going to 
lock up the liquor. You ought to be 
ashamed." 

Just then Aunt Henna stalked out from 
under the bed, tail high, padded feet taking 
her gracefully toward the babbling TV, 
"Sucker," she muttered. 

*1 tell you," I yelled to Amie, 'This 
damn cat talked to me. Go on, kitty, say 
something else!" All I got was a feline smile 
— or something in that cat-e-gory , 

The booze was promptly locked up. 

Later in the evening 1 sensed that Amie 
was sort of looking at me sideways. "Don't 
you think it would be wise to see Dr. 
Bingleflick? You haven't had a checkup in a 
long time. Besides, Katy Bingleflick tells me 
he just got his Extra Class ham ticket. Your 
Advanced deal somehow is not a word I 
would normally associate with you." 



62 



73 MAGAZINE 



*'Yes, dear." The rest of my reply, 
silently recorded, was to get me a private 
supply of vodka, which could be stashed 
away in the garage, ! was going to need It for 
sure. 

In ensuing weeks Aunt Henna gradually 
became more friendly, even sitting con- 
tentedly by me when 1 was on the air. She 
never would speak in Amie's presence — but 
on other occasions was pleased to tell some 
of the boys she was a six year old cat and 
got a bang out of ham radio* ''No kitten/' 
she was wont to add. That generally put 
them in the aisles — but obviously they 
suspected me of some sort of hoax. 

Out of deference to her growing erudi- 



tion, it seemed only fair to lay off the 
hockey stick business. She was soon busily 
learning to read, almost ignoring the TV- 
Evidencing a great interest in electronics, she 
was becoming expert on the subject, 
particularly anything to do with antennae- 
Then came an unexpected catastrophe. 
She lapsed back into form and ate our 
canary. It was a lovely spring afternoon* I 
was getting ready to string a new 40-meter 
dipole over the back lawn. The gilded cage 
had a neat little hasp on Its door — but 
somehow she got it open. Only a few yellow 
feathers lay under the cage by the patio 
rubber plant. She'd practically inhaled the 
bird. It was that fast. 



«H . ■:v>^;>v. ry 



*F^H ni»H^*M^#Baa^ 







AUGUST 1975 



63 



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Plus Your Choice of 2 Pair of Common Frequencies 
Extra Crystals, S4.50 ea., Common Frequencies Only 



$320 VALUE FOR jtsT 



n99 



95 



• 6 Channel Operation, Individual Trimmers 
On All TX and RX Xtals. Alt Xtats Plug In. 

• S Meter Battery indicator, 

• 10 J IF and 465 KC IF, 12 KHz Ceramic Filter, 
. .3 Microvolt Sensitivity For 20dB QT, 

• 2,5 Watts, Wominal Output 12 VDC. 

• Microswitch Mike Button. 
. Si^e 8-7/8 x 1-7/8 x 2-7/8 Inches. 

• Weight 1 lb. 4 ounces. Less Battery. 
. Current Drain RX 14MA TX 450 MA. 

ACCESSORIES: 

SMI Speaker Mike $24.00 

BCI Battery Charger S29.95 

1410A Amplifier Mobile Mount S99.00 

XF-1 10.7 MHz monolithic »F filter (installed) St 0.00 

TE 1 Continuous sub-audible tone encoder (installed) S39.95 




COMING 
SOON Ml 

220 & 420 MHz 

HAND HELD 

TRANSCEIVERS 




To: Wilson Electronics Corp, 
P.O. Box 794 

Henderson, Mevada 89015 
(7021 451 5791 

Ship 1402 August Packages 



piusUsMi ni4ioA Dbci D xf-1 Dte-i 



Enclosed is S 



□ Check □ Money Order 



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Card 
Xtals 



# 



Name 



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CAN BE MODIFIED 
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Signature 



Zip 



All orders will be shipped Parcel Post within 48 hours after 
receipt of order texcludfng weekends). Enclose additional S4hOO 
for prepaid shipping & handltng. Nevada residents add sal&s tax. 

Sale ends August 31. 197&. 



A r ANNOUNCES ITS tt 



NEWEST EDITION 

WILSON 1405SM HAND HELD 
5 WATT FM TRANSCEIVER 

^ NEW SLIMLINE UNBREAKABLE LEXAN®CASE 
ijcSWITCHABLE 1 or 5 WATT OUTPUT 
ijc EXTERNAL EARPHONE MIC JACK 
jjc EXTERNAL POWER JACK 

+ FACTORY OIRECT AUGUST SALE INCLUDES: 

Rubber Flex Antenna, NtCad Batteries, Leather Case, 52/52 
Crystals, Plus Your Choice of 2 Extra Pairs of Common Fre- 
quency Crystals. Extra Common Pairs, $9.00 pr. 



90 DAY WARRANTY 

10 DAY MONEY BACK 
GUARANTEE 



CAN BE MODIFfED FOR 
ARMY MARS OR CAP 



$390 VALUE 



ALL 
FOR JUST 



«269 



» 




6 Channel Operation, Individual Trimmers on all TX and 
RX Xtals, All Xtals Plug In. 
S Meter Battery Indicator, 

10.7 IF and 455 KC IF, 12 KHz Ceramic Filter, 
.3 Microvolt Sensitivity For 20dB QT. 
5 Watts Nominal Output 12 VDC. 
Microswitch Mike Button, 
Size 8-7/8 X 1-3/4 K 2-7/8 Inches. 
Weight 1 lb* 4 ounces, Less Battery. 
Current Drain RX 14MA TX 800 IVIA. 
ACCESSORIES: 
SM2 Speaker Mike $24.00 
BC2 Battery Charger $29.95 

XF*1 10.7 MHz monolithic IF filter (installed) $10,00 
TE-1 Continuous Sub-Audible Tone Encoder {installed) 
$39,95 



To; Wilsor> Electron ia Corp. 
P O Bow 794 
Henderson, Nevada 890 1 5 
(702) 4B1 5791 



1405 August Packages 



Ship— ^^ 

PliisDSM2 nBC2 DXF'I DTE-I 



M/C Interbank — 



Enclosed is S 

D Master Charge nSank Americard 
Expiration Date 

Card - 

Xtals 



• D Check D Money Ordef 



Xt- 



Name. 



Address 



Citv and Ststa 
Signature .^^_ 



Zip 



Ail orders will be shipped Parcel Post within 48 hours after 
receipt of order lexcludinQ weekends}. Enclose additional S4.00 
for prepaid shipping & handling. Mevada residents add sales tax. 

Sale ends August 31 « 1975. 




I shook an admonishing finger at her, a 
bit at a loss for words. She was daintily 
wiping her whiskers with a paw, studying a 
Sears Roebuck catalogue. Anything that had 
to do with the word cat stirred her interest. 
Her great, fluffy tail waved gently. ** Mister/' 
she said, *'wouId you like me to help you get 
that dipole up?" This was an abrupt change 
of subject, a feint to divert the lecture she 
knew t was about to deliver. 

For years it's been a ritual to don my 
** Robin Hood"-Bavarian climber's hat, 
complete with feathers, when preparing to 
string up a new antenna between trees. My 
trusty bow and arrow can almost always 
arch the arrow over the highest sturdy fork 
of branches available, bringing with it a 
thread, then line and pulley. Without the hat 
and a good shot of vodka I'm liable to shoot 
myself in the foot 

'*You look foolish in that gear/* said 
Aunt Henna, *'You want me to help you get 
that wire up in the air?" Her voice trailed 
off, then returned suddenly, ''Hurry down 
to Railroad Salvage and save^ save^ save, 
brother! 430 people were drowned when the 
ferryboat turned turtle. A raging fire has 
now become a holocaust in the stricken 
city . . . -' 

*'Hold it, Aunt Henna/' ! cried. Her boob 
tube categories were merging in general 
confusion. '*Just how do you propose to 
assist?" I asked, trying to get her back in the 
groove, '* Perhaps this is a bit over your 
head." 

**Since my mean altitude is only about 
ten inches, it better be, Mister, if you expect 
to get out anyplace," 

*'Not anyplace — anywhere," I 
admonished. "Your English is simply dread- 
ful," 

Well, in short order Aunt Henna had 
started up the 80-foot pussy willow tree, the 
thread, with a small weight attached to its 
end, in her mouth. Up, up she went, 
occasionally jumping to an adjoining trunk 
of the huge tree. At about 65 feet I shouted 
for her to drop the weight over a crotch- 
Down it came beautifully. 

With the mission accomplished, she then 
stretched out on a branch, her great tail 
flicking this way and that, which It always 



did when she was thinking deep thoughts. 
**You know, Mister," her voice drifted 
down, "it was a mistake eating that bird." 

"Yes, I know. It was very naughty." 

"Oh, I don't mean that It's given me a 
wicked stomach ache. It's been a lousy day, 
with awful TV programs. That yellow bird — 
canary you call it? — was the catalyst that's 
brought on one of my dizzy spells," 

This was alarming, **Just hold on tight," I 
called, "until it passes. You'll be all right- 
Take a cat nap or something," 

''My middle, with that miserable canary 
in it, is supported between my front and 
hind legs in catenary suspension." Her voice 
was growing weaker, "You get it, Mister?" 

In the instant I was mulling that one over, 
there came a screech from on high — and 
down came Aunt Henna tumbling through 
the spring foliage. She hit with an enormous 
thump and lay still- I rushed over and bent 
down. 

She opened one eye and murmured, 
'*This is the end, a cataclysm!" 

"Oh, no, Aunt Henna, I'll get you down 
to Dr. Bingleflick — he'll fix you up." 

"He's for humans — not a cat doctor." 

"Veterinarian, please," i corrected. "But 
since you are almost human , , ." 

"Thanks a lot," she said, now back on 
three of her feet, tail twitching violently — 
and a ground dragging droop in her middle- 

We stopped off in the garage so I could 
brace myself slightly. Two or three good 
slugs of vodka seemed in order. Noting her 
gleaming eyes, both of them now back on 
duty, I held out the bottle. "Like some?" I 
asked, 

"just a touch," she replied, *1 found 
where your Amie hid the key to your main 
grog supply-" 

"And that was?" 

"In the ashes of her cremated Uncle 
Jake's urn, which she keeps on the top shelf 
with her hats in your closet-^' 

From her rambling comments, it 
developed that Aunt Henna had been 
nipping on the main supply for some time. 
The afternoon's exploits, including demoli- 
tion of the canary and plunge from the 
willow tree, related to an over abundance of 
cat nips- She was now wabbling and weaving 



66 



% 



73 MAGAZINE 



around some pamt cans. "Are we going to 

Dr, Flickbingle's?" she asked. Her eyes were 

slightly crossed, or perhaps I was looking in 
my workbench mirror at the moment. 

ft suddenly occurred to me that Amie 
had the car. Here we were in the garage and 
it definitely was not around* **lf you don't 
mind/' I apologized^ **we1I take Amie's 
bicycle - OK?" 

Aunt Henna jumped into the basket. 
'*You better open the door as a precaution 
for a dignified exit. Your Amie won't like it 
if you bang up her hike/' 

It was easy to ignore such flippant 
remarks, considering their source. I couldn't 
help admiring the old cat, as she stood 
proudly in the front basket, her feet slipping 
through this way ^^^^^^~^^^^^^ 

and that as she Here's to a cat 

lurched around for a 

footing. ^^^ ajg ^ f^j bird 

*Tet us be off/' 
she ordered* In a similar vein 

Dr. Bingleflick's Which one was 

office was on the 

other side of the 



iook at that guy/' she yelled- '* What's he 
doing? I smell birds!" 

A sort of grid-platform stepladder was in 
place at the front of the outboard jet engine 
on our side- A mechanic with a big mesh 
screen in his hands was descending the 
ladder. In the screen were what seemed to be 
a mess of ducks, starlings, geese, or what 
have you — mostly mushy looking stuff, 

"Looks like those birds weren't so smart 
tangling with that big job/' I offered, 

•m 

*'Yeah/' said Aunt Henna, "This I must 
see/' With that she jumped down and in a 
graceful arc of motion was up on the 
platform stepladder 

By this time, the mechanic was trundling 
his screen full of crunched birds toward the 

hangar. He paused 
for an instant, look- 
i ng up at an 
engineer gazing 
from the pilot's win- 
dow. **OK - Jack, 
She was et by a plane blow her and you'll 

clear the rest of the 
trash/' 



Named Aunt Henna 



For her denner 



The wickeder sinner? 



town, close to the airport^ which we would 
pass on our way. For some odd reason, the 
road had become very unsteady, 
like a rippling, waving ribbon^ hardly suit- 
able for bicycling. 

Anyhow, as we came abreast of the 
airport, Aunt Henna let out another great 
screech, pointing with her bad foot at a huge 
four-engined jet that was parked close by. 

Slamming on the brake, I nearly went 
over the handlebars. '*What in the world is 
the trouble?" 

"That's the fantastic plane they were 
telling us about on TV! It can take off 
straight up," 

''So-o what?'* 

"So — this I've got to see closer. Please, 
can we go in?** 

Aunt Henna had a most persuasive way 
about her. After all, why not humor her? It 
was a lovely spring afternoon. We were in no 
hurry, at least I wasn't 

Jumping from her basket, she was up on 
top of the Cyclone fence in a flash, her tail 
swishing around like a kid's pinwheeL *'Hey, 



An accelerating whirl of enormous noise 
screamed into being as the engine started up. 
Aunt Henna was on top of the ladder, 
clutching with all three feet and part of the 
other one. For a second or two she managed 
to hang on ^ but there was nothing to get 
her claws in- Then she departed into the 
engine with tremendous velocity, a blurred 
flash of fur. She had simply vanished in the 
gigantic suction. 

The speed of it all was shocking. It took 
me some moments to get hold of things. 
Then, pedalling slowly homeward, it all 
seemed rather just retribution. Cat eats bird 
— airplane eats cat. . , 

Certainly there was no need to tell Dr. 
Bingleflick any of this. There was no proof. 
Nothing. He would surely have good reason 
to have me put under observation. As for 
Amie, she wouldn't believe anything any- 
how. There was only one answer! Tell 
Wayne Green , , * He wouldn't dare print it 
in 73 . • . The boys would be sure he was 

nuts . . . 'By, now. 

, , .W1 



AUGUST 1975 



67 





No w in stock 
The latest synthesized rigs available. 





ICOM 230 



146-148 

FM 



ITC Multi-2000 



144-148 

FM-CW-SSB 








Brimstone 144 



142-149 
FM 



EBC 144 Jr J 43.5 148,5 

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ICOM 21 -A 
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146 148 



Tennelec Memory Scanner ^i^n^i^n^JJ^ 

450-51 MHz 



AUDIO LAND is now offering hi^ trade-in prices for your used equipment. Write 
for trade-in prices and price quotes. Now in stock - CUSHCRAFT — REGENCY - 
SBE - HAL COMMUNICATIONS - NEWTRONICS - HY GAIN - AMPHENOL 
- TURNER - E.V. - SHURE - STANDARD - TEMPO. 3000 xtals for most rigs. 
Rotors and cables. Stereo and Quad equipment - and much more. N.P.C. regulated 
power supplies. All major charge cards accepted. Several finance plans available. 
Write for our latest trade-in listing. 

OUR HAMS SERVE YOU ! 
Sales: Earl K8BHP - Chris WB80HK - Dave WB8TOB 
Service: Jerry WB80HJ - Jerry K810E 




36633 S. Gratiot 
Mt Clemens, Michigan 
791-1400 



48043 




68 



73 MAGAZINE 



D, W. Butner W7SHY/6 
P.O. Box 3887 
Chico CA 9S926 



Copp 




Rip 



Off 



After a recent move^ as often happens, 
an urgent construction project came 
up before some of my tons of boxed junk 
had been unpacked. A PC board was needed. 
My plastic bottle of ferric chloride was 
nowhere to be found. 

I needed to whomp up a mixer board and 
did not want to use a perforated breadboard. 
As is true with most mixers, I needed all the 
shielding I could get. About ten years ago I 
saw a board for an emitter follower that 
someone at the Navy Research Lab had 
made by cutting the foil rather than etching 

it. My rat's nest memory said, *Try it/' 
An Ideal method is to use a hand-held 



high speed rotary drill with a burr bit. Not 
having one, I used an ole faithful ]4** drill, 
with a small rotary saw blade. The results, as 
pictured, are in the ** worst possible case** 
category, but the technique worked. The 
mixer was built and was successful. 

Also pictured is a more civilized, carefully 
made, professional looking example of 
mechanical removal of copper clad, ^ 

The point is, however, that you can 
prepare a PC board mechanically, whether 
by sawing, reaming, burring or using an 
Exacto knife, rather than by chemical etch- 
ing, if it becomes necessary to do so, 

. . - W7SHY/6 





The ''worst possible case'' category, done 
with a rotary saw blade. 



AUGUST 1975 



A more professional looking example of 
mechanical removal 



69 



Dave Ingram K4TWJ 
Rte. 11, Box 499 
Eastwood ViL #504 N. 
Birmingham AL 35210 



Better Results from those 

Sy^reep Tubes 







^ 



WH^— Wa fuWiU ■ I 






H 



^ 




w 







Sweep tubes have come of age, and are 
appearing in more and more ham transr 
mitting gear. The first group of sweep tubes 
to appear in transceivers, 6GE5s, 6GJ5s, 
6JB6's, etc., were of the 200-300 W class, 
Soon their "big brothers/* like the 6JE6s, 
6LQ6s, etc, became more prevalent, running 
a solid half gallon* Now, these tubes are 
finding their way into many linears, both 
commercial and home brewed • Sweep tubes 
are very popular because they are quite 
efficient and relatively inexpensive. 

Listed herein are some tips which I have 
found that will help assure longer life and 
improved efficiency from these ''little 
bottles/' 

A fan is the most worthwhile investment 
you can make, since most rigs restrict the air 



Photo by Don Langston WB4JVY, 



flow around the final amplifier to a marked 
degree. Heat is the main killer of not just 
sweep tubes^ but a! I tubes • A small fan 
blowing across the final Is better than no 
fan, and it can be mounted to the side of the 
final or even placed on the desk beside the 
rig- However, a fan above the final pulling 
the air up is preferred. 

It's best to mount the fan directly over 
the final amplifier compartment. Vibration 
can be reduced by the use of felt pads under 
the mounting bracket(s)- I have found this 
to extend tube life and efficiency to a 
marked degree. Needless to say, this is 
practically a necessity with the 500 W 
transceivers, or high power tinears. 

A choice fan for this application is the 
fan manufactured by Rotron and Delwin^ 
like the whisper, muffin and skeleton fan; 
they are quiet and they move plenty of air. 



70 



73 MAGAZINE 




SPECIFICATIONS 

Frequency Range 500 Khz— 250 Mhz 

Sensitivity Less than 80 mV at 150 Mhz 

Input Z...(500 Khz to 10 Mhz) 1 Meg. 

Input Z...(10 Mhz to 250 Mhz) 50 ohms 

Max. Input Voltage 15 V rms, 50 V dc 

Time Base Crystal Clock plus-minus 10 ppm 

CC to 40°C ambient 

Readout 6 Digit 7 Segment LED 

Power 1 20 V ac 

Dimensions Tk" H. 1 0" I, T D 

Cabinet Light Blue 



BANKAMEmCAHU 



fi'th*!**^ Af>i 



f 



master charge 



tHi iHi'^MsAHK cnci 



K-EISlTEF1f=H=lieES 



I^ 



Model 4x6 250 Mhz 

FREQUENCY 
COUNTER 

250 Mhz for M.O0 per Mhz 
Wired and Tested 




Price FOB Shawnee, Olcla. 

Include *2.50 for Postage 
& Insurance 

Model 4xG-C Wired & 
Tested with Temperature 
Compensated Oscillator & 
Temperature Certification 
furnished with coun- 
ter... .'270.00. 



K-ENTERPRISES 1401 E. Highland • Shawnee. Okla. 74801 



When adding the fan, try one on the 
power supply also. Most transceiver supplies 
run pretty hot, especially the 500 W units, A 
fan will at least keep the transformers and 
diodes cool enough so you can touch them 
without second degree burns. 

If you use a sweep tube linear, either 
commercial or home brew, try to use as low 
idling current (high bias) as practical — this 
extends life appreciably. One easy way to do 
this is to increase the bias until the output 
just starts to drop off using an swr bridge or 
watt meter for indication (I assume the rig is 
already tuned and drive is applied as usual 
for full CW carrier). This bias setting is 
usually close to optimum and linearity is 
usually excellent. 

Another method, when an output indica- 
tor is not on hand, is to increase the bias 
(from a very low value) while the tubes are 
idling with no drive until the plates cool 
from cherry red to a no-color condition. 
Usually the plates will show color (blood 
red) after a no-drive idling state for about 30 
seconds when the idling current is too high 
(bias too low). 



On CW use minimum drive; in fact, it's 
best to cut power (by inserting less carrier, 
not by loading rig lighter) to about one-half 
the sideband rating unless your keying is 

around 15-20 wpm and then only two-thirds 
the sideband rating would be the most 
practical value. 

The swr is especially critical on CW and 
an swr of even L5:l may cause these tubes 
to blush even more under key-down condi- 
tion. It is also a good idea to note the exact 
dial settings of the loading and plate tuning 
on all bands to prevent an off resonance 
condition when tuning up. With a simple 
chart of all settings the plate need never 
come off resonance by more than 30 
milliamperes. Tune-up time can be reduced 
further by the use of a scope or modulation 
indicator, A meter takes time to **settle,^- 
whereas a scope is accurate immediately, 

So^ there you have it. Try some of the 
ideas presented above and see if youVe not 
happier with your sweep tube rig, I'm sure 
you will be pleasantly surprised, 

. , , K4TWJ 



AUGUST 1975 



71 




DOES ANY OTHER MORSE CODE KEYBOARD 
HAVE ALL THESE FEATURES? 

3l Programmable Memory 
right on the Keyboard 

3l Running Memory lets you Type 
up to 72 Characters Ahead 

3l Variable Speed from 6 to 35 WPM 

3t Memory Overload Indicator (LED) 

tl48 Hour Burn-In Prior to Shipment 

ZL Space Bar is used for Word Spacing 

3l Computer Grade Switches and Key tops 

HE Cooling Fan to Assure Long Component Life 

X110 VAC Operated with Built-in Audio Monitor 

E Double Sided-Plated Thru- G10 Glass Printed Circuit Board 

11 Black Naugahyde Finish on Metal Case with Walnut End Plates 



1 ORDERING INFORMATION | 


model' 


PROGRAMMABLE 
MEMORY INCLUDED 


PRICE 


TS-172 


One 


$369.95 


TS-272 


Two 


$389.95 


TS-372 


Three 


$409.95 


TS-472 


Four 


$429.95 


TS-572 


Five 

i 


$449.95 


TS-672 


Six 


$469.95 



r 




I 



TELSTAR ENTERPRISES 

P. O, Box 235 

Spo!<ane, Washington 99215 



. D Enclosed is $ 



D Charge Master Charge /^_ 

□ Charge BankAmerJcard #. 

□ Send Free Brochure 

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72 



73 MAGAZI NE 



WiUiam E. Browning WB5IRY 
516 N. 95ih E. Ave. 
Tulsa OK 74115 



The Best Logic Yet 



When I first got into amateur radio 
just about three years ago, I had a 
little understanding of the way tubes 
worked. I decided that if I built anything for 
the shack it would be with tubes - and that 
I would just buy anything that had to use 
that mysterious solid state. 

This decision did not last for long, how- 
ever. I just don*t like having to buy every- 
thingj since I'm really a builder at heart So 
all that was left for me to do was start 
learning about solid state, I started building 
some projects from the pages of '*73" and 
some other magazines — some worked and 
some didn*t* When they didn't^ 1 was usually 
lost as to why. 

Then I found that the projects that used 
what was called TTL logic usually worked 
the first time and that when they didn't I 
could usually find out why. Over a period of 
a few months I had formulated a list of 
fundamentals that almost assured that the 
projects would work. 

Presented here are some of those funda- 
mentals from my notes. If you use them as a 
guide line I know you can do as well or 
probably better at TTL projects than I have. 

FIRST: The power supply for TTL is one 
critical spot. The absolute maximum voltage 
for most of the TTL ICs is 7 volts, with 5 
volts being normal. Stay within 4.5 and 5.5 
volts, 

SECOND: Find the output pins, and do 
not connect two outputs together. 



THIRD: If you use the 5 volts from the 
power supply for an input signal on an input 
pin or for any reason put the 5 volts from 
the power supply to an output pin without a 
load, connect a resistor in series (any size 
from 100 Ohms to 10k Ohms will work in 
most cases). 

If you follow these first three design rules 
you will find that it is almost impossible to 
damage the ICs and you can now experiment 
with them all that you want to. 

Now that we are not going to send the IC 
up in smoke, let's see what we will find 
inside some of them and how we can put 
them to work for us. 

The first one to look at, which is the 
simplest of all, is the buffer. With the buffer 
the output is the same as the input It is used 
to isolate the input circuit from the output 
and also to drive more circuits than your 
input signal may be able to. The logic 
symbol for a buffer is shown in Fig. 1 . 

With the buffer, if we put **0'* volts or 
ground on the input, the output will be '*0" 
volts. If we put 5 volts (often referred to as 
logic 1) on the input, the output will be 5 
volts (logic 1 ). See Fig. 2, 




Fig. h 



AUGUST 1975 



73 



You will notice that the input is a square 
type wave; this is the type of input that 
digital circuits need to work properly. There 
are input circuits that will let us use sine 
wave inputs and some special ICs which are 
designed for a sine wave input, but for now 
we will stay with the square type input 

One digital \C which uses the buffer is the 
7407 hex buffers/ drivers. This chip has six 
buffers on the one IC Each buffer can be 
used separately- (The layout of the chip is 
shown in Fig. 3.) 

Note that +5 volts goes to pin 1 4 and that 
ground is on pin 7. This supplies power for 
operation of all six buffers. With an input on 
pin 1 you get an output on pin 2, while an 
input on pin 3 will give you an output on 
pin 4, input on 5 for output on 6, input 9 
for output on 8, etc. 

One thing that works out nice for testing 



5V- 
0¥ 



ITLil^ 



INPUT 




JUUL 



OUTPUT 



Fig. 2. 




is that if an input is not connected to 
anything (is floating), the IC sees it as logic 1 
(5 volts) and the output goes to 5 volts. If 
the input is grounded (logic 0) the output 
goes to volts. You can test a chip by 
watching the output on a voltmeter as you 
ground and unground an input. 

FOURTH: Comtdera '*Fioating'' input as 
logic /, 

If an input is to be at volts make sure 
that it is connected to ground. 

The next "gate" to look at and experi- 
ment with a little is the inverter. It is almost 
the same as the buffer, with one exception: 
its output is always opposite from the input* 
The logic symbol for an inverter is shown in 

Fig. 4, (The only difference between the 
symbol of an inverter and the symbol for a 

buffer is the small circle at the output) 




Fig. 4, 

With the inverter, volts or ground on 
the input will ©ve you 5 volts (logic 1) on 
the output, and 5 volts on the input (or a 
floating input) will give you volts on the 
output See Fig. 5. 

One digital IC which uses the inverter is 
the 7404 hex inverter^ This chip has six 
inverters on the one IC. Each inverter can be 
used separately. The layout of the chip is 
shown in Fig. 6- 

Note that on the 7404, +5 volts is on pin 
14 and that ground goes to pin 7, This 
supplies the power for operation of all 
inverters. With an input on pin 1 you get 
your output on pin 2, while an input on pin 
3 will give you an output on pin 4, etc. 

It is possible to use an inverter as a buffer 
by putting two gates in series. As an example 
using the 7404, you could connect pins 2 
and 3 together, place your input on pin 1 
and take the output from pin 4, The output 
now will be the same as the input just like 
with the buffer. See Fig, 7< 

One other thing that you may Want to 
keep in mind about the inverter is its other 
name: the "NOT'* gate. This comes from the 
fact that its output ts NOT the same as its 
input. But whether you call it an inverter or 
you call it a "NOT" gate, it is the same thing 
with the same symbol 

Another gate that you will find in the 
logic famify is the "AND" gate. It is similar 
to the buffer, the only difference being that 
it has more than one input. The logic symbol 
for an "AND** gate is shown in Fig. 8. 

With the "AND'* gate, both inputs must 
be at logic 1 (5 volts) before the output will 
be logic 1. This is where the gate gets its 
name: input 1 AND input 2 must both be 1 
{5 volts) to get a 1 for an output. See Fig. 9. 

The "AND" gate can also be used as a 
buffer and there are two ways to do it. One 



5V' 
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73 MAGAZINE 




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way is to put a constant 5 volts on one of 

the inputs and put your input signal on the 
other. (If you use this method use a resistor 
in series with the 5 volt power supply.) The 
other way is to connect the two inputs 
together and put your input signal into both 
at the sanne time. See Fig. 1 0, 

One digital IC which uses the "AND" 
gate is the 7408 quad 2Hnput AND gate. 
This chip has 4 "AND" gates on one IC 
Each gate can be used separately; the layout 
of the chip is shown in Fig, 1 1 , 

As with the other chips, the +5 volts is 
put on pin 14 and the ground is put to pin 7. 
Input 1 and input 2 go to output 3, Input 4 
and input 5 go to output 6, etc. 

In some circuits it is desirable to have the 
two inputs with the AND function, plus the 
signal inversion of the NOT gate (inverter), 
This is now easy to do by using the two 
gates together* See Fig, 1 2, 




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The use of the "NOT" and the "AND" 
gate together is a very common com- 
bination, so common in fact that it is 
considered as another gate called a 
NOT- AND" gate or even more frequently a 
NAND" gate. So remember, when you see 
"NAND", that it is just an "AND" gate 
followed by a "NOT" gate. These two gates 
are often combined on one chip as one gate 
and the symbol for the combination^ the 
"NAND" gate, is shown in Fig. 13. 

You will notice that the only difference 
in the symbol of the "NAND" and the 
symbol of the "AND is the "o" at the 
output of the gate. In the use of logic 
symbols the "o" will indicate that the signal 
is inverted. 

One digital IC which uses the "NAND" 
gate is the 7400 quad 2-input NAND gate. 
This chip has 4 "NAND" gates on the one 
IC. Each gate can be used separately; the 
layout of the chip is shown in Fig. 1 4. 

As can be seen, +5 volts goes to pin 14 
and ground goes to pin 7. Inputs 1 & 2 go to 
output 3, inputs 4 & 5 go to output 6, etc. 
The 7400 is one of the most widely used ICs 
of the TTL logic family, since it can be used 
as a buffer, as an inverter or "NOT" gate, as 
an "AND" gate, and as a "NAND" gate. 
Whatever the operation you have in mind, 
the 7400 can be made to work. Not bad for 



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AUGUST 1975 



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Fig, 13. 




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Fig. 14, 



an IC that can be picked up for under a 
dollar. Fig. 15 shows how to connect it to 
work as the different gates. 

Another type of gate that you may come 
across is what is known as an '*OR'' gate. It 
is similar to the **AND'* gate with one 
exception: With the "AND" gate you had to 
have 5 volts (logic l) on both inputs 1 and 2 

to get logic 1 (5 volts) for an output With 
the *'0R" gate, a 5 volt input on input 1 or 



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gate as is. 



Use each 



'* or ''NOT'' 



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''Inverter 

— Connect the two 

inputs together, or 

connect one input to 

+5 volts and use the 

other input for your 

signal 




**AND'' — Feed the 
output of one 
''NAND*' gate into a 
second gate that is 
conne c ted as a 
"NOT" gate, and take 
your output from the 
second gate^ 



C4 




Buffer'* — Feed the 
output of one gate 
con ne c ted as a 
"NOT" into a second 
gate connected as a 
''NOT", and take 
your output from the 
second gate. 



Fig. 15. 



Fig, 16, 

2 will give you logic 1 output* The logic 
symbol for an *'0R" gate is shown in Fig. 
16, and its operation is outlined in Fig. 17. 

One digital IC which uses the *'OR" gate 
is the 7432 quad 2-input OR gate. This chip 
has 4 "OR'' gates on one IC. Each gate can 
be used separately; the layout of the chip is 
shown in Fig. 18. 

As with the other ICs that we have 
looked at, the +5 is to pin 14 and ground is 
to pin 7, Inputs 1 and 2 go to output 3, 
inputs 4 and 5 go to output 6, etc. 

In some circuits it Is desirable to have the 
two inputs with the OR function, plus the 
signal inversion of the NOT gate (inverter), 
It is easy to use the two gates together as 
shown in Fig. 19. 

The use of the NOT and the OR gate 
together is also a very common combination. 
The combination is usually considered as 
one gate called a NOT-OR gate or, more 
commonly, a "NOR" gate. The logic symbol 
of a "NOR'' gate is shown in Fig. 20. 

Note that the only difference in the 
symbol of a "NOR" gate and the symbol of 
an '*0R'* gate is that the "NOR'' gate has a 
"o'' at the output. 

FIFTH: Const der a "o" at any chip to 

show the signal is inverted at that point. 

One digital IC which uses the *'NOR" 
gate is the 7402 quad 2-input NOR gate. 

This chip has 4 NOR gates on a single IC. 
Each gate can be used separately; the symbol 
for the chip is shown in Fig. 21 . The +5 goes 



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76 



73 MAGAZINE 



*5V 


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to pin 14, ground to pin 7, inputs 2 and 3 to 
output 1 , inputs 5 and 6 to output 4, etc. 

With this chip you can have the operation 
of a "NOR" gate, the operation of a "NOT" 
gate (inverter), the operation of an "OR" 
gate, and the operation of a "buffer". Fig. 
22 shows the connections for the different 
gates. 

Two other \C gates that you may run 
across are: 

1) The 4-input "NAND". There is not 
much difference between a 4-input g;3ite and 
the 2-input gate that we looked at before. 

With the 4-input "NAND" gate, all 4 inputs 
must be at 5 volts (logic 1) to get volts at 
the output. If any input is ground (logic 0), 
the output will stay at 5 volts. See Fig. 23 
for the logic symbol of the 4 input 
"NAND". 

2) The 8-input "NAND". With this gate 
we find that all 8 inputs must be at logic 1 
for the output to be at logic (ground). If 
any of the inputs is at ground, the output 
will stay at logic 1 (5 volts). See Fig. 24 for 
the logic symbol of the 8-input "NAND". 

I have not tried to show all of the ways 
that TTL logic can be used or all of the 
different types of gates that you may see 
from time to time. I have not included 
anything on flip flops, decade counters, or 
any of the more complex ICs, most of which 
would take an article the size of this one to 
discuss fully. 



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What I have tried to do is show some of 
the fundamental logic gates that make up 
most of the TTL logic circuits. If you have 
an understanding of the operation of the 
"buffer", the "inverter" (NOT) gate, the 
"AND" gate, the "NOT-AND" (NAND) 
gate, the "OR" gate and the "NOTOR" 
(NOR) gate, you are ready to start building 
with TTL. 



My suggestion now is to get a 5 volt 
power supply, and 2 or 3 7400s, and see just 
what they will do. Then pick a project from 
the pages of "73" Ma^zine, and try it. 
Don't be too surprised if it works the first 



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time the power is turned on. If it doesn't, 
look back over the fundamental gate opera- 
tion and J*ll bet you find out why in a very 
few minutes. 

Above all, remember ^'Browning's Rules 
of Order": 
A Stay within 4, 5 and 5. 5 volts. 



AUGUST 1975 



77 



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2. Do not connect two outputs together. 

3. Connect a resistor in series with any input 
or output which goes to the 5 volt power 
supply. 

4. Consider a "floating*' input as logic 1. 

5. Consider a "o" at any chip to show that 
the signal is inverted at that point, 

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79 



How to 

COM PAC T 
MULTIBAND 

DIPOLES 

Peter Fischer VE3GSP 
J 379 Forest Glade Road 
Oakville, Ontario Canada 

Often the need arises for a temporary or 
permanent low cost antenna. Usually, a 
dipole or inverted vee antenna Is the logical 
choice. They are easy to install and certainly 
cheap to build. One of the disadvantages of 
such an antenna is that they are only usable 
on a single band, unless they are fed with an 
open feeder line (300—60012) in combina- 
tion with an antenna tuner. This article 
describes two types of dipoles for operation 
on A) 80, 40 and 15 meters; and B) for 80 
and 20 meters. 

These dipoles are fed with a random 
length of 50f2 coax, and they can be strung 
as straiglit dipoles or inverted vees. The 
latter configuration makes it easier to adjust 
the antenna for resonance and requires only 
one high support. Each antenna leg has one 
loading coil to obtain the desired resonance 
points on the described amateur bands. 

Theory 

Generally, centerfed dipoles can be fed 
with 50—75^2 coax if the current maximum 
of an operating frequency occurs at the 
antenna feedpoint* Therefore, a dipole with 
the leg dimensions of 67, 35, 1 8 or 1 1 ,5 feet 
will show a feed point impedance of 50-7512 
for 80, 40, 20 or 15 meters accordingly, if a 
portion of each 67 foot leg (80 meter 
halfwave dipole) is substituted with a load- 
ing coil, and that loading coil is placed at the 
correct position, the dipole can be made to 
have current maxima at the feedpoint at 40 
and 1 5 , or at 20 meters. 

For example: If a loading coil is placed 
about 35 feet from the feedpoint, a current 
maximum will occur at the feedpoint for 40 
meters. With the correct coU dimensions and 




ANTENNA "A" SB 



SO METERS 



j"r*i"r^ 




ANTENNA 'A' 



/vw^r-^ 



40 METERS 




ANTENNA *A' ft *B' 



15 a 20 METERS 



Graph 1, Antenna current distribution. 

top- wire length, the dipole can also show 
current maximum at the feedpoint for 80 
meters. In both cases, the dipole functions 
electrically as a halfwave dipole, 

Coinciden tally, since the 35 foot wire 
portion from the feedpoint to the loading 
coU corresponds to 3 x 1/4 wavelength on 
15 meters, there will also be a current 
maximum at the feedpoint for 15 meters. 
Thus, the antenna will work on 80, 40 and 
1 5 meters when fed with a 50—75^1 coax. 

The son coax (RG8U, RG58U) is fa- 
vored as the loading coils decrease the 
feedpoint impedance from a theoretical 7 5^2 
(classical halfwave dipole) to about 500. 

If the leg- and coil -dimensions are altered, 
the antenna can be made to work on 80 and 
20 meters. Here, the antenna functions as a 
halfwave dipole on 80 and as a 1^2 wave 
dipole on 20 meters. 

Ten meter operation is possible with both 
antennas, but the swr is in the order of 3:1 
or worse. 

Antenna Dimensions 

Dipole A - 80, 40 and 15 meters 
Overall length: 2 x 41.5 feet 
Leg dimensions: 61 feet of wire, coil^ 5 
feet of wire 

Dipole B - 80 and 20 meters 
Overall length; 2x61 feet 
Leg dimensions: 53 feet of wire^ coO, 5 
feet of wire 
See Graph 1 , 



80 



73 MAGA7iNF 



Antenna Assembly and Coil Data 

Prepare the loading coils for the desired 
dipole, model A or B. For coils (antenna A) 
densely wind 70 turns of #20 copper 
enamelled wire on to a 114 inch O.D. plastic 
body. Use 24 turns for coil antenna B. 
Plastic sewer pipe is suitable and readily 
avaOable everywhere. You need about 2x5 
inches for A and 2 x 3.5 inches for B for 
convenient assembly. The coil windings are 
secured and weatherproofed with varnish or 
better with epoxy glue. The wire ends are 
soldered on to bolted solder lugs, which also 
serve to connect the antenna wire to the 
coils. (See Fig. 1.) 

The antenna wire should be #14 or #16 
copperweld for adequate strength. The di- 
pole center is a porcelain strain insulator; it 
secures the wires at the dipole center and 
permits you to solder an SO-239 coax 
receptacle to the wires for easy coax connec- 
tion. The far ends of the dipole are ter- 
minated on porcelain eggs. I recommend 
nylon or other nonmetallic line for fasten- 
ing the porcelain eggs to a support. If wire is 
used, corona flashovers occur across the eggs 
at higher power levels. 

Calculating Wire Length 

Both dipoles should be cut specifically 
for your primary operating frequencies. Pre- 
cise wire length can be calcuiated from the 
formulas given below, provided you stick 
with the recommended coU dimensions. 
Note that the wire lengths for 80 meters (A 
and B) include the wire portion from the 
center to the coil plus the coil to the 
porcelain insulator at the antenna ends. 



Antenna A 
80 meters: 

40 meters: 

15 meters: 



Ft, per leg 
Ft. per leg 
Ft. per leg 



153000/kHz 
250000/kHz 
750000/kHz 



Obviously, if you optimize your 40 meter 
resonance for 7200 kHz you cannot reach 



£i^ 




COILS 



Fig. I . CoU layou L 



optimum conditions on e.g., 21.100 kHz, 
since the 15 meter resonance occurs 
automatically on 3 times the frequency than 
that of 40 meters. You therefore have to 
compromise slightly. 7,100 kHz seems Uke a 
good compromise, keeping in mind that the 
swr on 1 5 meters is fairly low over the entire 
band- 

Antenna B 

80 meters: Ft, per leg ^ 227000/kHz 
20 meters: Ft. per leg = 750000/kHz 

Tuning Procedure 

First the antenna is adjusted for reso- 
nance (minimum swr) on the high fre- 
quency bands, 40 and 1 5 or 20 meters. This 
is done by lengthening or shortening the 
wire portion from the feedpoint to the 
loading coHs. To increase the resonance 
frequency shorten this wire portion, and to 
decrease the resonance frequency lengthen 
the wire portion in each antenna leg 
symmetrically. A change in wire dimension 
will affect the resonance frequency for the 
80 meter band. Therefore, the 80 meter 
tuning is done next by shortening or length* 
ening the 5 foot wire portion between 
loading coils and porcelain eggs. This last 
adjustment is critical; about one inch of wire 
results in 20 kHz resonance change on the 
80 meter band. The second tuning step will 
not affect the first one. Do not forget to 
adjust both antenna legs symmetrically. 

Comments 

I tried both aiitcnna versions as inverted 
vees, mainly because it simplified the tuning 
procedure veiy much. The swr at resonance 
for antenna A was 1.1:1 at resonance on 80, 

40 and 1 5 meters. 

Antenna B showed an swr of 1.5:1 on 
80 and 1,1:1 on 20 meters at the resonance 
frequencies. I assume that the poorer 80 
meters swr results from a relatively low Q 
and L of the loading coil of antenna B . The 
signal reports on 80 and 40 meters were 
excellent, and 20 and 15 meters showed a 
difference of about 3 S-units in receive mode 
as compared to my 2 element quad antenna. 
The antenna can also be tuned with a 
grid-dip meter. 

. .• VE3GSP 



AUGUST 1975 



81 




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83 



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Special Supertuner handles 3 
KW PEP amplifiers — 

$229.50 ppd. USA 



This is the low cost way to 
match almost any random 
length wire on the five most 
used HF bands. 

• Covers 80 through 10 meters 

• Handles maximum legal power 

• Matches random length long 
wire antennas 

• Features Dentron quality and 
value 

Model 80-10 Antenna Tuner 

$49.50 ppd. USA 



/ 





TECO 




P.O. BOX 1050 

a subsidiary of Tucker Electronics Co. 

1717 S. Jupiter Rd. GARLAND, TX. 75040 

800-527-4642 toll free 
In Texas Call 214-348-8800 



AlJfitJST 1Q7R 



85 



r 





SUMMER 
1975 



i\ 



A SUBSIDIARY OF TUCKER ELECTRONICS CO 



SPECIAL SALES FOR THE HOBBYIST, AMATEUR AND BARGAIN HUNTER. 

INVENTORY REDUCTION SALE!! 

Quantities are very limited on many items. 
When calling, ask for Test Equipment Sales 

The instruments listed are surplus unless otherwise stated. Each unit is sold as is and every attempt is made to assure completeness. While 
most instruments are operational, no warrantee is implied or stated. There is a 10 day trial period for each instrument which allows you to 
inspect and assure yourself that you are satisfied. You may return the instrument for full crec^! ijnng this 19 day period-paying onfy Ireight 
charges Since rl is impossible to list the individual condition of each mslrument-call and discuss your choice- Should vou desire the same in- 
strumenl completely reconditioned and guaranteed, we can put you in touch with ouf parent company for price and ava»iabjlity information. 

CREDIT ' TECOS terms are casfi or COD with the following exceptions. TECO accepts BankAmer*card, Master Charge and Amencan Ex- 
press. TECO will sell on net 10 days to O&B or credit established customers. Our aim ts to keep our overheads as low as posstbte so we can 
continue to offer instruments at the very lowest prices. Please help us to meet our goals and send your check with your order. 





MILITARY TS-723B/U (HP 330B) DISTORTION 
ANALYZER 

This marvelous noise and distortion analyzer gives 
accurate direct readings from 20 Hz to 20 KHz. Per- 
fect for nneasuring audio distortion, voltage level, 
power output, gain, distortion of AM RF carrier, 
nneasuring hunn and noise level and audio signal fre- 
quency. Blanketing the audio spectrum the TS*723 
measures noise levels as small as lOO^V and distor- 
tion as low as 0.1%. A wide-band 20dB gain amplifier 
is built in as well as a VTVM witln nine full scale 
ranges from 0.03 to 300 volts and nine dB ranges 
spaced exactly lOdB per range from - i2dB to + 2dB. 
Residual frequencies are measured to within ± 3% of 
full scale value. TECO S special sale price is 



LEEDS & NORTHRUP 5430 A (MILITARY ZM-4B/U) 
RESISTANCE BRIDGE. 

This advertised special is a portable, general purpose 
wheatstone bridge designed primarily to measure re- 
sistances when locating faults which occur in conduc- 
tors used for communications systems and those 
used for power transmission. It can also measure the 
value of any fixed resistor. In addition to the self* 
contained galvanonr>eter it has provision for external 
null indicator and batteries. Measures resistance val- 
ues from O.DOl to 1,011.000 ohms, internal battery 
power supply. Ratio dial multiplying values for resis- 
tance measurements and Varley loop tests are 
1/1000. 1/100, 1/10, 1/9, 1/4, 1, 10 and 100. Ratio 
for Murray loop tests are Ml 000, Ml 00 and Ml 0, Ac- 
curacy is ± 0.1% of indicated resistance . . $75*00 




TECO 



a subsidiary of Tucker Electronics Co. 



P.O. BOX 1050 1717 S. Jupiter Rd. GARLAND, TX. 75040 

800-527-4642 toll free 
In Texas Call 214-348-8800 



86 



73 MAGAZINE 



HICKOK 1890M TRANSISTOR TESTER: Measures 
in-circuit Beta and Rin of transistors and leakage ot 
out-of-circuit transistors, ± 5% Beta measurement 

accuracy , . . — $75.00 

MILITARY UPM-6B Radar Test Set: For deck testing 

of Mark VIFF equipment .$65*00 

MILITARY UPM-12 SWR INDICATOR TEST SET: 
Used to make impedance measurements In X-band 

waveguide equipmerrt J1 50.00 

MILITARY UPM'17 SPECTRUM ANALYZER: 
Military version of Lavoie LA-18M, general purpose 
spectrum analyzer covers lOMHz to 16 GHz. 

TECO Price ....-•,,-. , ,$595,00 

POLARAD R100 KLYSTRON TUBE 

TESTER: .. ., .$100,00 

POLARAD PJ-1 PUtSE JITTER TESTER: $125.00 
POLARAD TSA SPECTRUM ANALYZER MAIN- 
FRAME: Resolution 2-80 KHz, dispersion 400 KHz to 
25 MHz, sensitivity -SO to -95 dbm, variable at* 
tenuator, built-in marker. Other plug-ins available to 

44 GHz , From $1 50.00 

SINGER SSB-3B SINGLE SIDEBAND SPECTRUM 
ANALYZER: A comprehensive communications sys- 
tem analyzer with five preset and one contmuously 
variable sweep widths. 2pLV sensitivity switch selecta- 
ble 50 or 600 ohm input impedance and resolutfon 
variable from 10 Hz to 3 KHz tnternal markers and 

many features , . . , $1 295.00 

SINGER (TELESIGNAL) TA216B TEST SET: 

Includes interconnecting cable . . . . , ,$155,00 

SPRAGUE TCA-1 CAPACITOR ANALYZER: $50.00 
STELMA TDA-2 RTTY DISTORTION TEST SET: 

TECO Price . • . • - - . . $20,00 

VIDAR 720 FLUTTER ANALYZER: Seven operating 
frequencies from 3,125 KHz to 200 KHz. fiutter band- 
width from 312 Hz to 10 KHz, Built-in scope, solid 
siaie unii ««**.. .*i »»■ ,,,,),■ t9wOv*w 



FREQUENCY MEAS- 
URING EQUIPMENT 



BECKMAN 7570 CONVERTER MAINFRAME: 

Accepts 7570 series converter plug-ins to expand 
basic range of counters using heterodyne 

technique , . $35,00 

BECKMAN 7571 PLUG-IN CONVERTER: 10 MHz to 

110 MHz $25.00 

GERTSCH FM-3 FREQUENCY METER: Measures 
20-1000 MHz with 0.001% accuracy, generates over 

same frequency $1 95.00 

GERTSCH FM*4 FREQUENCY MULTIPLIER: 
Measures and generates signals from 500 MHz to 
12.5 GHz, requires 400-1000 MHz driving 

GERTSCH FM-7/DM-3 FREQUENCY METER: 

Includes deviation meter, measures and generates 
signals from 20-1000 MHz with 0.001% 



HP 524B COUNTER: DC to 10 MHz, 6 digit neon, 2 

meters $95.00 

HP 524D COUNTER: DC to 10 MHz, 8 digit 

neon $1 45.00 

HP 52SB CONVERTER PLUG-tN: 110 MHz to 220 

PVI f I ^ .~ P'~r-r*t**--^ -..a pvi lav f-p.BPW*'«<>«ivw«>w ""^F ' ^ • 'Vl^ 




SIGNAL GENERATOR 



ALFRED 620 SWEEP OSCILLATOR: 5 to 10 

GHz.N output at lOmWatts , . , .$395.00 

ALFRED 622 BK SWEEP GENERATOR: Complete 

unit covers 2-4 GHz range .,.,,......, .$395,00 

ALFRED 623B SWEEP GENERATOR: Complete 

sweeper covers 4-8 GHz range $395*00 

ALFRED 624B SWEEP GENERATOR: Complete 

sweeper for 8-12.4 GHz range $395.00 

ALFRED 625B SWEEP GENERATOR: Complete 

unit covers 1 2.4 to 18.0 GHz . . ^ ^ $395*00 

ALFRED 642K SWEEP GENERATOR: Compleie 2-4 

GHz unit ___... $795.00 

DUMONT404 PULSE GENERATOR: MOO KHz rep 
rate, 0.02 to 100/i.sec pulsewidth, 3V into 600 ohms, 

0-50dB attenuator . , , $65,00 

EH 120D PULSE GENERATOR: 100Hz to 20MHz. 
20V into son, 1,3ns rise at 20V, variable pw, dual 

putse .$295,00 

EH 121 PULSE GENERATOR: 10Hz to 10MHz. 4ns 
rise ±50V into 500. Variabie widtti with fixed I20ns 

delay • $295.00 

FXR S77tB TEST OSCILLATOR: 1,9-4.0 



GHz. 



^ r n 



m k * f * * * 



h t k d 



$175.00 



FRX C772A SIGNAL GENERATOR: 3 95 to 8.2 GHz, 
10-100mW output, internal square wave modulation, 

external pulse and FM ....... ........ .$195.00 

GENERAL MICROWAVE 301 POWER SUPPLY: 
Powers GMC noise generators in 501 series $20.00 
GR 605B STANDARD SIGNAL GENERATOR: 9.5 

KHz to 30 MHz - . . . $100.00 

GR 1208B UNIT OSCrLLATOR: 65 to 500 MHz, re- 
quires unit power supply , , * .$80.00 

GR 121 8 A UNIT OSCILLATOR: 900 MHz to 2 GHz, 

requires unit power supply ...,.., ,$125.00 

GR 1390A RANDOM NOISE GENERATOR: 

30Hz*5MH2. 1 V output $95.00 

HP 20SAG AUDIO OSCILLATOR: 20 Hz to 20 

KHz , $250.00 

HP 205AH HIGH POWER OSCILLATOR: 20 Hz to 
20 KHz 5 watts output into 50, 200. 600, or 5000ft. 
Buitt-in attenuators, input and output meters. $275.00 
HP (BOONTON) 207E UNIVERTER: Extends range 

of 202 series generator .$125.00 

HP 61 6A SIGNAL GENERATOR: Direct reading and 
direct control from 1.6 to 4.2 GHz, The HP 61 6A fea- 
tures ±1.5dB calibrated output accuracy from 
- 7dBm to - 127dBm. The output is directly calibrated 
in microvolts and dBm with continuous monitoring* 




TECO 



a subsidiary of Tucker Electronics Co. 



P.O. BOX 1050 1717 S. Jupiter Rd. GARLAND, TX. 75040 

800-527-4642 toll free 
In Texas Calf 214-348-8800 



87 





GENERAL ELECTRIC PORTABLE METERS indude snap-on 
curacy. These excellent instruments are priced to move quckly 

SINGLE RANGE UNITS . . - 

MULTIPLE RANGE UNITS ,, 

AC Ranges In Stock: 

to 0.75/1.5 KW; to 1.5/3 KW; to 30/60A; 

to 10 /20V: to 15 /30V: to 25/1 50V; 

to 150V: to 150 /300V. 
DC Ranges in Stock: 

to 500^: to 1 mA; to 300 mA; to 3A; to 30A; 

to 3V; to 7.5/30 /75V; to 150V. to 150 /300V; 

to 150/300 /750V; to 300V. to 600V; to 750V, 



self contained cover, carrying handle and 0.5% DC ac- 
so get your order in today. 

$20.00 each 



METiRS OF ALL TYPES 



ASSOCIATED RESEARCH 259 VIBROGROUND: 

Similar to Model 293 .$65.00 

ASSOCIATED RESEARCH 293 VIBROGROUND: 

Lightweight instrument for measurement of soi!- 
resistance and ground resistance, 0-1/10/100/1000 

ohms , *$80.00 

BALLANTINE 300 VTVM: ImV to 100V. 10 Hz to 150 

KHz , .$25.00 

BALLANTINE 305 PEAK READING VTVM: 
Measures P-R positive or negative peak values, 5 Hz 
to 500 KHz response ImV to 1000V with mirror back 

& W d I t^ i4kltt.ld.±lk..J.....x....i<..^.j.|.3 + L+ 9' ■V ^ ■ 1' V 

BALLANTINE 31 OA VTVM: 100 /xv to 100V. Meas- 
urements from 10 Hz to 2 MHz. 3% accuracy to 1 

MHz , , $75.00 

BALLANTINE 314 VTVM: 1 mV to 1KV, 15 Hz to 6 

MHz. less probe , .... .$75-00 

BALLANTINE 316 VTVM: Peak to peak. 0.05 Hz to 

30 KHz $35-00 

BIRD 61 S4 WATTMETER: Direct reading 20 or 5 
watts (choice), 50n. N(F) connector, Includes 

meter _ , $65.00 

BIHD 694 WATTMETER: to 1000W direct reading. 
2 to 36 MHz. 50fi. N(F) connector ......... $195.00 

BOONTON 91 CR RF VTVM: 1 mV to 3V. 20 KHz to 

1 .2 GHz, rackmounl , . .$225.00 

BORG WARNER (SINGER) M401 SWR INDI- 
CATOR: ' $95.00 



CARY MODEL 31 VIBRATING REED ELEC- 
TROMETER: ImV to 30V In 10 ranges $50.00 

E-H RESEARCH 140A SWfTCHING TIME METER: 

FLUKE 910 A TRUE RMS VOLTMETER: 10 Hz to 7 

MHz IOOmV to 300V fs. ± 1% accuracy $225.00 

FXR B810A SWR METER: . . . , $35.00 

GENERAL MICROWAVE 451 POWER METER: 

TECO Price . . ... $35.00 

GR 1932A DISTORTION METER: 50 Hz - 18 KHz. 

TECO Price . . $1 25.00 

HP H18-340B NOISE FIGURE METER: Automatic 
display and measurement of IF or RF amplifier noise 
at 30 and 60 MHz, Operates with external noise 

sources for other bands $400.00 

HP 400DR VTVM: 10 Hz to 4 MHz, 1 mV to 300V, 2% 
accuracy .............................._ .$65.00 

HP400HR VTVM: 10 Hz to 4 MHz, 1 mV to 300V, 1% 

aCCUfaCy , , i * t ^ * * • • m . r * •, * m *'• • * **«. ■■.■< +v93.vU 

HP 41 2A RDC VTVM: 1 mV to 1KV, 1 microamp to 
1A, can be used as DC amplifier, 2% 

accuracy $1 95.00 

HP 415A VSWR INDICATOR: $25.00 

HP 41 6A RATIOMETEfl: Displays ratio of fomard 

and reverse signals automatically $125.00 

HP 41 6B RATIOMETER: Later version of 

41 6A $395.00 

HP 500C TACHOMETHY: 180 RPM to 6,000.000 

RPM $85.00 

ITE (PHAZOR) 10DA PHASE SENSITIVE NULL 
METER: 30 Hz to 10 KHz. 8 volts to laOV reference. 
Separates in-phase and quadrature null voltages. 40 

dB selectivity $95.00 

KtNTEL 202BR DC MICROVOLTMETER: Full scale 
ranges from SOO^V - 1000V r 3%. can be used as 
70dB amplifier $35,00 



CAUTION: THESE INSTRUMENTS ARE SOLD AS-IS. WHILE EVERY ATTEMPT IS MADE 
TO ASSURE COMPLETENESS AND TO DELIVER AN OPERATIONAL INSTRUMENT. 
THERE IS NO WARRANTY IMPLIED OR STATED EXCEPT; "YOU MAY EXAMINE THE 
UNIT FOR TEN DAYS AND. IF YOU ARE NOT SATISFIED. YOU MAY RETURN FOR FULL 
CREDIT PAYING ONLY THE FREIGHT CHARGES". EVERY TECO INSTRUMENT IS CON- 
SIDERED TO BE A GENUINE BARGAIN. BUT THE BUYER SHOULD HAVE ACCESS TO 
COMPETENT TECHNICAL TALENTS TO MAKE THE PURCHASE PRACTICAL. 

SEND FOR THE LATEST "BARGAIN HUNTER" BROCHURE - ITS FREE! 





88 



73 MAGAZINF 



METERS OF ALL TYPES 

Contlnuecl 




ORION V-100M VTVM: Similar to HP 400H. like 

new ,.,.,_. $60.00 

NARDA MODEL 440 SOLID STATE MICROWAVE 
POWER METER: Rechargeable batteries . . $95.00 
PRD 277B STANDING WAVE INDICATOR: $75.00 

PRO 650 POWER METER: ..,.,,. .$40.00 

SRI AEW EDGESCALE METER: to 50/100/200 

VDC ranges. 7 ' scale, 0.5% $25*00 

SRI AEW EDGESCALE METER: 250 VDC range. 

7" scale, 0,5% $20.00 

SRI CEW"7 EDGESCALE METER: to 200 VDC, 7" 

scale, 0.5% .,,. $20,00 

SRI JW'4A EDGESCALE METER: lo 1.5/6 mVDC 

ranges, 4'' scale. 0.5% .$30.00 

SRI JW-iA EDGESCALE METER: to ISO nnVDC 

range. 4" scale. 0,5% $20,00 

SRI JW'4A EDGESCALE METER: to 150 mADC 

range. W scale, 0.5% . , , $20.00 

WILTRON 321 PHASE & AMPLITUDE INDICA- 
TOR: Includes local oscillators from 2.5-1000 MHz 

TECO Price $1 395.00 

AIL 130 PRECISION TEST RECEIVER: 30 MHz IF. 

O'SOdB precision attenuator , .$250.00 

HAMMARLUND SP600 RECEIVER: 560 KHz to 54 

MHz .$225.00 

MILITARY URTM-7 RFt MEASURING SET: 
Measures boradband and CW interference. Fre- 
quency range is 20-400 MHz in two bands. Voltage 
range is 6juV to 5V/MHz. Contains an impulse 
generator for notse reference standard. ± 1 0% volt- 
age accuracy .,.,..... . , , $995.00 

NEMS-CLARKE 1401 TELEMETRY RECEIVER: 215 

to 260 MHz range ..... $95.00 

NEMS-CLARKE 1412 RECEIVER: 215-260 MHz. 
crystal controlled with deviation meter. 100/500 IF 



bandwidth 



www 



1 ¥ p 



R ^ F- -i 



$75.00 



NEMS-CLARKE 1432 TELEMETRY RECEIVER: 215 
to 260 MHz range, identical to 1412 except uses 

phase lock detector $75.00 

NEMS-CLARKE 1455 RECEIVER: 215-260 MHz. 
crystal controlled or internal VFO, 150/300 IF 
bandwidth $1 25.00 



RECEIVERS 



POLARAD R RECEIVER BASIC UNIT: Nine plug-ins 
cover 400-84.200 MHz range. AM, CW, FM, MCW or 
pulse reception. IF bandwidth 3 MHz. video bandwidth 
2 MHz, sensitivity - 50 to - 90 dBm. Requires plug-in 

to operate ...,...« * * $350*00 

POLARAD R SERIES RECEIVER PLUG-IN: Nine 
plug-ins cover 400-84,200 MHz. Specify correct 



STODDART NM^SOA RFI RECEIVER: 375-TOOO MHz 
receiver, excellent units .$595,00 





BALLANTINE 300 VTVM: The model 300 is a sensi- 
tive, wide bank VTVM with a 100.000 to 1 voltage 
range and accuracy of better ttian 2% anywhere on 
the scale and at any frequency from 10 Hz to 150 
KHz. Specific ranges allow measurement from ImV to 
100V with an inpyl impedance of 0.5M11 shunted by 
30pF, The voltage ranges are logarithmic and there is 
a matching to 20 dB linear decibel scale. 
Special while they last ..,.,. , $29.50 



band 



■ ■■*>< 



$300.00 



HP 434A CALORIMETRIC POWER METER: Just 
connect to the Type "N" input and read the power 
from lOmW to 10 watts anywhere in the frequency 
range from DC to 12.4 GHz. No external terminations 
or detectors * readings direct Jy in watts or dBW. 50 
ohms input with internal calibrator circuit and :!:S% 
accuracy. (Accuracy at low end of frequency range is 
as good as 0.5%). New price exceeds $2000.00 

MILITARY TS-537 TSM CRYSTAL IMPEDANCE 

METER. 

With a frequency range from 75 to 1100 KHz in 6 

ranges and measurement scales from to 99,000 n 
and 12 to 110 nanofarads thts portable, general pur- 
pose, test instrument is designed to measure equival- 
ent electrical parameters of quartz crystals of the type 
used for communications purposes. Provision is made 
to measure directly the effective series*resonant and 
anti*resonant resistances of a piezo-electric quartz 
crystal in its holder. The load capacitance is obtained 
by applying dial markings to a calibration chart. With 
the static capacity measured by an external capacity 
measuring device and with the senes-resonant and 
anti-resonant frequency measured by an external fre- 
quency measuring device, the series capacitance and 
inductance can be calculated. A microammeter indi- 
cates the magnitude of oscillation of the oscillator tube 
by measuring its grid current. Frequency is selected by 
a switch and a fine tuning control. Equipment can be 
bench or rack-mounted , ,$55,00 




TECO 



a subsidiary of Tucker Electronics Co. 



P.O. BOX 1050 1717 S. Jupiter Rd. GARLAND, TX. 75040 

800-527-4642 toll free 
In Texas Call 214-348-8800 




AUGUST 1975 



89 



/I 



MILITARY UPM-4A TRAKSPONDER TEST SET: 
Three piece unit in single cabinet includes power sup* 
ply, simulator unit and oscilloscope display unit. The 
UPM*4A performs many measurements on radar 
equipment operating in the 925 to 1225MH2 range in- 
cluding checks on decoding, receiver bandwidth and 
frequency, receiver sensitivity, pulse counting, pulse 
analysis and IFF target generators. This unit sold 
new for nearly $5000 but at TECO its cost is a 

$175,00 



low 



« < t f ■- ' 



» « * 4 



MILITARY AN/UPM*15 200 VOLT PULSE 
GENERATOR. 

A Portable, general purpose pulse generator set used 
for testing pulse amplifiers and networks, and for 
modulating osctllators in field and depot maintenance. 
ft generates single or double pulses of variable repeti- 
tion rate, width, amplitude, separation, delay and rise 
decay time. The pulses may also be synchronized 
with oscillators or other instruments. Output rep rate is 
externally or internally variable from 50 Hz to lOKHz, 
pulsewidth variat)le from 0.5 to lOO/i seconds, am- 
plitude 0.002 to 200 volts and calibrated delay from 2 
to 225Msec An extraordinary vaiue ..,,.,... ,$50.00 
TEKTRONIX 1121 AMPLIFIER: SHz to 17MHz. gain 

of 100 $175.00 

WEINSCHEL CF-1 AF SUBSTITUTION AT- 
TENUATOR; For use with square low de- 
tector ,, , . . , ,$150.00 

WCINSCHEL IN-1 AUDIO LEVEL INDICATOR: For 
use with square low detector $50.00 



MILITARY TEST EQUIPMENT is the biggest value 
for your money. Each military unit is ryggedized and 
constructed of the highest quality parts. The U*S* 
government has put severe MIL-SPECS into each of 
their purchases assuring YOU an instrument now that 
bears the U.S.A. mark of quality and yet is usually 
less expensive. Examine the Military units carefully for 
BEST BUYS — call TECO for your requirements that 
cannot be filled by this brochure. TECO has 
thousands of instruments that, due to space limita- 
tions, are not shown in this brochure. 



OSCILLOSCOPES 
AND RELATED 
INSTRUMENTS 



HP 185 SAMPLING OSCILLOSCOPE: DC to 

1GH2 - $195.00 

HP 11 00 A DELAY LINE: 120nsec $75.00 



• 



•5 







%%\ 







• 



1^ 
1 

r 



¥ 



TEKTRONIX OSCILLOSCOPE PLUG-INS: Can be 

used with the 530. 540 or 550 series oscilfoscopes 
with equal performance. 

Model 53/540 dual trace 20 MHz unit $95.00 

TEKTRONIX CA PLUG-IN: DC -24 MHz dual 

$150.00 



■•lb. %'~t9 ^ 9 



■ V4>»i4»l#»*« itff bip 



trace 

TEKTRONIX E PLUG-IN: DC -60 KHz 

differential ..».*.».,» * - * .$75,00 

TEKTRONIX DIFFERENTIAL PLUG-IN: 50mV to 
20V/cm sensitivity. DC to 20 MHz bw, 18ns 

risetime , .$65*00 

TEKTRONIX H SINGLE TRACE PLUG-IN: 50mV to 
20V/cm sensitivity. DC to 15 MHz bw, 23ns 

V 1 3 C? 'I'll sS •>•••>■••■■■*«>**»■< •'■E*i>i**iiBa»i<«»i! ^P I ^r 1 \f \M 

TEKTRONIX K SINGLE TRACE PLUCrN: 50m V to 
20V7cm sensitivity, DC to 30 MHz bw, 12ns 

risetime $50.00 

TEKTRONIX R PLUG-IN: Transistor risetime $65.00 
TEKTRONIX 262 PROGRAMMER: Remotely pro- 
gram the 6R1 A digital unit $250.00 

TEKTRONIX 535 OSCILLOSCOPE: DC to 11 MHz 

less plug-in $425.00 

TEKTRONIX 536 OSCILLOSCOPE: DC to 15 MHz 



less plug- in 



# h i i * r n i « 



■ » I -fa 



$350.00 



RECORDERS AND 
PRINTERS 



BRUSH RE3610-60 100 CHANNEL EVENT RE- 
CORDER: as-is' .. $150.00 

EAI8AR CHART RECORDER: 40 channeis record- 
ing time 9, 18. 27 hours $150.00 

FAIRCHILD 321-A OSCILLOSCOPE RECORD 
CAMERA: Continuous motion 35mm camera with 

magazine and variable speeds $75.00 

HP 560A DIGITAL PRINTER: Up to 11 columns 
capacity with plug-in boards. 5 line/second print 




TECO 



a subsidiary of Tucker Electronics Co. 

P.O. BOX 1050 1717 S. Jupiter Rd. GARLAND, TX. 75040 

800-527-4642 toll free 
Texas Call 214-348-8800 





90 



73 MAGAZtNE 



Simple operation, frequency dial accuracy is ±\% 
and stability exceeds 0.005% /'C change m ambient 
temperature. Caiibrated attenuator is within ±1,5dB 
over entire output band. 50 ohm impedance unit has 
internal pulse modulation with rep rate variable from 
40 Hz to 4 KHz, variable pulsewidth (1 to lO^sec) and 
variable pulse delay (3 to 300^sec). External modulat- 
ing inputs increase versatility. New price exceeds 

$2000.00- TECO PRICE $395,00 

HP (BOONTON) 207G UNIVERTER: Extends range 

of 202 series generators , , , $175.00 

HP 212AR PULSE GENERATOR: 60 Hz to 5 



KHz 



r ^■ -tt 



$65,00 



HP 2t8A/2t9B DIGITAL DELAY GENERATOR 
WITH DUAL PULSE PLUG-IN: Superb units have 

many features .$375,00 

HP 233A CARRIER TEST OSCILLATOR: 50 Hz to 
500 KHz. 3 watts Into 600 ohms, tests loops over 200 

miles long _ .$75,00 

HP (BOONTON) 240A SWEEP SIGNAL 
GENERATOR: Designed for alignment of broadband 
amplifiers, 4.5 to 120 MHz range. Output I^V to 

HP 616A SIGNAL GENERATOR: 1.8 GHz to 4 2 

GHz $395.00 

HP 684C SWEEP GENERATOR: 4 to 8 J GHz range. 
sweep rates 16 MHz to 160 MHz/sec in 9 steps. 

1 0mw output Bad BWO $195.00 

HP 686A SWEEP OSCILLATOR: Electronic sweep 
with sweep rate from 32MHz to 320Hz/sec In 9 steps. 

8.2 to 12.4 GHz range _ . .$195.00 

HP 686C SWEEP GENERATOR: Same as 6B4C ex- 
cept 8.2 MHz to 12.4 GHz umt ,, $195.00 

HP gaSA MICROWAVE OOUBLER: 9 to 13 in, 18 to 

26 GHz output at 1 0mW , . .$995,00 

HP (DYMEC) DY5731 HIGH POWER SIGNAL 
GENERATOR: X-Band. +24 to - 76dBm . . $495.00 
HOLT AO-1 AUDIO OSCILLATOR: 20 to 20 KHz, 

less than 0.1% distortion _ $125.00 

JERROLD CM-6 PORTABLE CRYSTAL MARKER 
GENERATOR: Six crystat markers between two and 

100 MHz, up to 20tt> harmonic .... $150.00 

JERROLD 601 SWEEP FREQUENCY 

GENERATOR: 12-225 MHz. SOft output, small 

JERROLD 900A SWEEP GENERATOR: 500 KHz to 

1 200 MHz, many features * *,•-*-. .$395.00 

KAY MEGA-NODE SR VARrABLE NOISE 
GENERATOR: 1-3000 MHz, 50n output, 0-20dB 
noise figure measurement. ±0,25dB accuracy $75.00 
MAXON 1141 A POWER OSCILLATOR: 200 to 2500 

MHz. 5 to 40 Watts output . . .$495.00 

MEASUREMENTS 80 SIGNAL GENERATOR: 
Covers UHF from 2 to 400 MHz and to lO.OOOptV 

calibrated output . , , .$295.00 

MEASUREMENTS 82 SIGNAL GENERATOR: 20 Hz 
to 50 MHz. to 50V output. 0-50% internal 
modulation .....«.., . .$250.00 



MEASUREMENTS 84 TV SIGNAL GENERAL: 30 
MHz to 1000 MHz, 75 ohm, O.VV to IV 

output , , . . , $175.00 

MEASUREMENTS 88 FM SIGNAL GENERATOR: 

88 to 108 MHz. 0.1 to 100,000/iV output $150.00 

MEASUREMENTS 188 FM SIGNAL GENERATOR: 
88 to 108 MHz, 0,t to 10O,OO0piV Output . . .$350.00 
MEASUREMENTS 21 OA SIGNAL GENERATOR: 86 
to 108 MHz. FM generator with 0,5% dial accuracy. 

son 0,1 to lOO^OOO^V output $125.00 

MILITARY TS-382 AUDIO GENERATOR: 20 Hz to 

^UU r\nZ - . - . . . ^ . « ^ . , , , . .."**.,..... + .. + ,» ^. ^$q5/00 

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Requires ' G" series plug-in to operate ..... .$350.00 

POLARAD G SERIES TUNING UNIT FOR HU-2A: 7 
unjts cover band from 18.0 go 39.7 GHz. tOmW aver* 
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tenuator and wave meter . , , _ . *^ $300.00 each 

PRD 903 SIGNAL GENERATOR: 7*1 1 GHz, CW. FM 

pulse ...,,.. _ . _ . .$1 95.00 

PRD 904 VHF-UHF NOISE GENERATOR: 30-1000 

IVI rii^ .**«»«.(,.,.,.,,,,., ,,,,,«,,,,^,,,, ^9^3UfUU 

RUTHERFORD B-2A PULSE GENERATOR: 10Hz to 

1 00 KHz, variable parameters , . .$45.00 

RUTHERFORD B-7 PULSE GENERATOR: 20 Hz to 

2MHz. all variable parameters $125.00 

RUTHERFORD B-7B PULSE GENERATOR: 20Hz to 

2MHz. late model of B-7 S22S.00 

RUTHERFORD B-14 PULSE GENERATOR: 20Hz to 

2MHz. solid State units .$125.00 

SIERRA 21SB-470 POWER OSCILLATOR: 150 to 

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TMC TT6-2 TWO-TONE TEST GENERATOR: 25 Hz 

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Hz to 1 MHz $75.00 

TEKTRONIX leOA TIME MARK GENERATOR: 

Excellent units $1 95.00 





HP 233A (MILITARY SG-71 B) CARRIER TEST OS- 
CILLATOR: A bargain tiunter's delight. The 233A 
checks carrier current systems and much more. This 
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over the frequency band from 50 Hz to 500 KHz mak- 
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used simultaneously for other tests. New price ex- 
ceeds S700,00 
TECO price for this special $75.00 



CAUTION: THESE INSTRUMENTS ARE SOLD AS-IS. WHILE EVERY ATTEMPT IS MADE 
TO ASSURE COMPLETENESS AND TO DELIVER AN OPERATIONAL INSTRUMENT. 
THERE IS NO WARRANTY IMPLIED OR STATED EXCEPT; "YOU MAY EXAMINE THE 
UNIT FOR TEN DAYS AND, IF YOU ARE NOT SATISFIED, YOU MAY RETURN FOR FULL 
CREDIT PAYING ONLY THE FREIGHT CHARGES". EVERY TECO INSTRUMENT IS CON- 
SIDERED TO BE A GENUINE BARGAIN. BUT THE BUYER SHOULD HAVE ACCESS TO 
COMPETENT TECHNICAL TALENTS TO MAKE THE PURCHASE PRACTICAL. 

SEND FOR THE LATEST 'BARGAIN HUNTER- BROCHURE - ITS FREE! 





Alimi.c:T iq7R 



91 



Michigan Radio Doctor 

Michigan Mother Trucker 



Don 





the 





It seems that as the weeks go by, you read 
more and more about CB antics in the 
papers- As more drivers rebel against the 
government imposed 55 mph speed limit, 
the citizens radio service, better known as 
CB, is being used to avoid wallet thinning 
(and insurance cancelling) tickets. Approxi- 
mately 40% of all the big trucks on the road 
have CB radios in them to watch for 
"Smokey/* If you tune in channel 10 
(27.075 MHz) and live near a major high- 
way, you will probably hear the strange 
lingo. Some of it is easily recognized, and 
some of it is not Even though CB has a 
rather short useful range, due to frequency 
congestion and the illegal use of high power 
amplifiers^ it is still useful for about 1 miles 
mobile to mobile, 15 miles mobile to base, 
and 25 miles base to base. This is more than 
enough to watch for "Smokey" or to report 
accidents or other highway emergencies. 
Many state and local police monitor channel 
10 and/or channel 9 for just that reason. On 
many expressways between metropolitan 
areas, it can be 15 miles or more to the 
nearest phone or exit where help can be 
called. 

Unfortunately, there have been some 
areas of abuse by both the users and the law. 
Many police resent the truckers' use of CB 



to avoid tickets and speed traps, and in turn, 
use it to find out if they are known to the 
speeders. In some areas the police will issue a 
ticket for only one or two mph over the 
limit if they hear the offender on CB 
warning other truckers of where the ''Bears" 
are. It has also been known that they will 
write a ticket on an out-of-state vehicle for 
70 in a 55 zone, even if they don't actually 
see the driver going 70. If they heard the 
driver say, "We got the hammer down to 
that 70*', they apparently figure that you're 
from out of state and won't stay to fight the 
ticket. And after all, they heard you publicly 
admit to doing more than the limit. 

On the brighter side of the road, there are 
many great **Smokies" out there and many 
of them spend a lot of time talking to the 
truckers and telling them where the traffic 
tie-ups are and how to avoid them. 1 have 
even had the Illinois and Indiana Smokies 
tell me to "put the hammer down, the way 
is clear for 40 miles," and mean it. 

Oh, well! Let*s face It! No one wants a 
ticket or $25 fine, no matter why or how 
much he exceeds the limit, so here is a 
collection of words and phrases frequently 
used to describe what is happening on our 
highways. You too can decipher channel 10, 
but be careful: Don't feed the bears! 



92 



73 MAGAZINE 



Advertising 
Back Door 



Bear 

Bear Cave 
Beat the Bushes 



Beaver 



Break One-Oh 
Break Ten , 
Bushels 
Camera 
Channel 10 
Chicken coop 
Clean 

Comic Books 
Cotton Picker 



County Mounty 
Ears -^ 

Ea turn-up ^B 
Eighteen Wheeler 



Fat load 
Feed the Bears 
Five-flve 
Four 
Four ten 
Four wheeler 



Front Door 

Grass 

Green Stamps 

Green Stamp Road 

Hammer 

Hammer Do wn 

fn the Grass 

Mercy 

On the Move 

On the side 

Other Half 





Police car with lights on. 

Friend following behind you guarding the rear approach (the 
friend can be the truck you just passed two minutes ago). 

Any Police Officer. 

Police station or Highway Patrol post. 

Lead mobile driving Just fast enough to cause a police car to come 
out of hiding to Investigate^ but not fast enough to get a ticket; a 
sacrificial lamb^ looking real hard for Smokey. 

As in^ "Feed the Beaver" — give your money to Mama^ not to 
Smokey. 

Break on Channel 10. (I want to talk.) 

Break on Channel 10, 

As: '7 got 70 bushels '' - I bushel = WOO lbs. 

Radar unit used to check speed of vehicles. 

CB channel 10 — 27.075 MHz^ truckers ' paradise. 

Truck weighing station. 

b police seea 

Truckers* logs. 

Usually used in place of swear words, such as, "That cotton 
pick in ' Smokey gave me a cotton pickHr ticket. 
County Police or Sheriff 

Radio, also used to indicate antennas. 

Restaurant or truck stop. 

Semi-tractor-trailer truck (may have more or fewer than 18 
wheels). 

Ovenveight load. Each state has Its own load limits. 

Get a ticket 

55 as in 55 mph. 






Ten-four in spades. 

Automobite. 

Lead vehicle watching for Smokies in front of group. 

Median or off on side of road. 

Money ^ f green stamp - / dollar. 

Toll road. 

Accelerator pedal. 

Driving fast, as in: 'Tut the hammer down. " 

In the median. 

Oh My I Goodness sakesi Imagine that I Wowl 

Traveling. 

Pulled over onto the shoulder^ (Smokey has a four wheeler) 
Just listening, (I'm < . J- 

Husband or wife^ whoever is not speaking. 



iStSiii 



■'^-'-^ -rh~j#^- 



AlJr;iJ5?T1Q75 



93 



Plain Wrapper 

Picture Toiler 

Pickum-up 

Pregnant Roller 
S/?ate 

Put the Good 
Numbers on you 

Raf^e the leaves 

Ratchet Jaw 
Rest-um up 

Rig 

RIG 

Rocking Chair 

Roger Ro/lerskate 

Roller Skate 

Seatcovers 

Six Wheeler 

Smokey 

Smokey the Bear 

Smokey with Ears 

Ten-four 

"^Thirty Three 
10-33 

Threes on you 

Threes & Eights 

Tijuana Taxi 
Train Station 
Two Wheeler 

Two Way Radar 



Wall to Wall Bears 



We Cone!! 



Unmarked police car or state public service car. 
Police radar unit, 
PickHjp truck. 



VW. 



73, 88, etc. 

Last vehicle in a group^ bringing up the rear^ back door. 

Talk for a long time — usually at the wrong time. 

Rest area. 

Tractor. 

Radio (ears). 

Truck (or car) between the front door and the back doon A 
good place to be. 

Driver of a car who is more than 20 mph over the iimit; a! so 
known as Roger Ramjet, a cartoon character. 

Small car J compact, import, motorcycle (rare). 

Passengers^ especially good iooking passengers. 

Car with trailer. 

Any police officer. 

State Police. 

Police with CB radio or CB monitor 

Whatever the other guy said was absolutely right 

Accident or emergency message. 

Best regards (73), 

73 & 88 — Best regards^ love and kisses (also known as stack 
them eights). 

Police car with lights and insignia. 

Court with high guilty rate , * * kangaroo court. 

Motorcycle, 

Radar which can be used to monitor traffic while in a moving 
vehicle. Some Smokies are said to have two way ears^ no radar 
but a monitor. 

Any area with heavy police patrol, such as i-240 in IVIemphis, 
Tenn.^ 1-94 Berrian County^ Mich., the whole State of Ohio, 
and other areas where the Police enforce the letter of the law 
to extremes or conduct known traps. 

Stopping transmitting and just listening, 

. . . Michigan Radio Doctor 
Michigan Mother Trucker 



""EMERGENCY MESSAGES HA VE PRIORITY OVER ALL OTHERS. 



94 



73 MAGAZINE 



The Wonderful 



Warren Mac Do well W2AOO 
1 1 080 Transit Road 
East Amherst NY 14051 



M in i 



Chronometer 



The state of the art in electronics minia- 
turization for digital clocks has evolved 
to the point where digital crystal controlled 
wrist watches aie now commonplace. For 
the average cheapskate such as myself, a 
$200.00 digital wrist watch is out of the 
question. What I am about to describe 
however, is a miniature digital alarm clock 
that will fit in a 3 inch square cube — power 
supply, readout, speaker and all. 

This compact clock could possibly be 
constructed in a Zippo lighter case if printed 
circuit techniques were not employed. The 




power supply and alarm speaker would then 
have to be remote and you might well be 
wearing 1*' thick bifocals after completing 
this project 

Anyway, my particular mini alarm chron- 
ometer was constructed in the discarded case 
of a defunct Radio Shack Weather Radio, 
The entire cube shaped case has the internal 
dimensions of about 3 square inches. When 
completed, this little beauty contained 
power supply, 10 digit LED readout (6 
used), an alarm speaker and all necessary 
switching. 





I 



ii 



Complete clock, power cord and "power plug" transforrr^r. The case is that of a 
discarded Radio Shack Weather Radio. 



AUGUST 1975 



95 



The only external component was the 
power transformer which serves also as a 
power line plug. This particular transformer 
is a telephone company encapsulated 6-8 V 
ac unit, with wall plug built in. If I am not 
mistaken, these are used to provide dial light 
power for ** Princess'' telephones. Our 
particular transformer just happened to fall 
out of a passing telephone company truck 
and they never returned to claim it. This 
encapsulated transformer is self current 
limiting (short proof) and, therefore, does 
not require a line fuse for the completed 
clock. If you don't have many phone com- 
pany trucks passing your home, a conven- 
tional miniature 6,3 V ac, 500 mA filament 
transformer (imported type) can be fitted 
into the 3'' cube with all necessary space to 
spare. Then, the only component external to 
the clock will be the line cord and **conven- 
tionar* wall plug. 

The current drain of the entire clock is 
very low and well within the requirements of 
this small transformer. The greatest ''current 
hogs'' in digital clocks tend to be the LED 
readouts. A garden variety large single LED 
can draw as much as 20-30 milliamperes per 
segment, of which there are seven. This gives 
you a grand total of 210 milliamperes (worst 
case) when all segments are illuminated. 

Once again, the state of the art in LED 
readout manufacture has created very small 
encapsulated bubble (magnified) type 
devices containing 5 complete seven segment 
readouts. This entire 5 digit readout plugs 
directly into a common 14 pin DIP Inte- 
grated circuit socket. Our particular readouts 
were obtained from Radio Shack for about 
$2.98 per device (2 required). For those 
with Radio Shack stores nearby it is part 
#276-059 (7 Segment Monolithic 5 Digit 
Numeric Display). 

The average current per segment in these 
displays is about 5 milliamperes. That results 
in 35 milliamperes total per 7 segment digit 
(worst case) and 210 milliamperes (worst 
case) for all six digits when totally illumin- 
ated. Built-in magnification of the self- 
contained plastic bubbles provides excellent 
readability and the total life span of the 
device is comparable to any other LED 
device. 



BOTTOM VIEW 



ANODE SEGMENT A 



14 



CATHODE DIGIT HO 2 — 13 



ANODE SEGMEM B 



M.C. 



ANODE SEGMENT F 



CATHODE DiGkT NO. 4 



ANODE SEGMENT G 



12 



Fl 



10 



9 



S 




1 — CATHODE DIGIT NO. I 



ANODE SEGMENT E 



3— ANODE SEGMENT C 



4 -CATHODE DtGJT N0.3 



ANODE DEOMAL POINT 



6 — ANODE SEGMENT D 



7— CATHODE DIGIT N0.5 



NOJ pin IDENTtFECATION 



NOTCH CUT 
FROM N0.1 RN 



¥W 



SEGMENT DESIGNATIONS 

A 




D 



Fig, I, S082readout pin connections. 

These readouts are internally designed for 
strobed or multiplex operation. This means 
that the individual digits have separate pins 
or connections and the segments are all 
connected in parallel with a common pin 
connectlon- 

In multiplex or ''scanning^* operation, the 
individual digits are turned on (pulsed) at a 
very rapid rate and at the same time^ 
appropriate segments are also turned on. In 
this way, even though the segments are 
wired in parallel^ the scanning action gives 
you the illusion of separate digits. The 
scanning rate of course is much faster than 
the eye can follow but well within the 
repetition (frequency limit) that the LEDs 
can follow. Pin connections for the Radio 
Shack part i^76-059 are illustrated in Fig. 

The integrated circuit clock chip that we 
used is the Mostek 50250 (Radio Shack part 
#276-1715), This IC can be used to drive 
either a four or six digit display. In our 
opinion, the 6 digit display is much more 
impressive, accurate and useful, especially 
for amateur applications. The 50250 has 
both 12 and 24 hour timekeeping capa- 
bilities. The 12 hour timekeeping format 
requires a 60 cycle input as a clock fre- 



96 



73 MAGAZINE 



lOMHf 
CRYSTAL 



-to ^lO 





osc 


lOMHi 


7490 




1 


IMHI 














100K 
' — -vw ♦ 50 Hf 



CfiYSTAL 




5MH1 




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\ — W\* #- 50 Hf 



2MHi 
CRYSTAL 




lOOK 
7490 f — vys^ ►SO Hi 



IMHz 
CRYSTAL 




^10 -^(0 

lOOKHi 



7490 ^ 



7490 



lOKHr 



7490 



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tKKz 



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■* 



7490 



100 K 



50H2 



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CRYSTAL 



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7490 


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Hg. 2, 50 Hertz crystal time base ideas. 



quency source. In other words, for normal 
timekeeping the 60 cycle line frequency 
must be sampled by the IC The clock 
accuracy is thereby directly affected by the 
60 cycle power line frequency. When the 
power fails, the clock loses its frequency 
source and timekeeping also fails. 

For the 24 hour timekeeping function, 
the 60 cycle power line reference cannot be 
used. The 24 hour format requires a 50 cycle 
frequency source. The 50 cycle frequency 
source lends itseff well to a crystal time base 
for the clock and excellent accuracy. By 
using a few other inexpensive TTL {tran- 
sistor-transistor-logic) integrated circuits, a 
10 MHz, 1 MHz, 100 kHz or other crystal 
oscillator may be divided down to provide 
the necessary 50 Hz reference- See Fig. 2. 

The most common and available crystals 
are those of 100 kHz and 1 MHz. the 
majority of amateur receivers have a built-in 



calibrator crystal at 100 kHz. Removing this 
crystal for use as a clock frequency source 
will not destroy its function as a calibrator. 
In fact, by constructing the clock source, 
you now have frequency references at 100 
kHz, 10 kHz, 1 kHz, etc. The clock, while 
running in normal operation, will radiate 
calibration signals. While operating, this can 
become an annoyance. Therefore, shielding 
of the cfock may become necessary if placed 
near your station receiver. Crystal sources 
may be divided down to provide 60 Hz but 
oddball crystals are generally required* It is 
much easier to use the 60 Hz power line 
source for the 1 2 hour format. 

The 50250 is really designed for opera- 
tion as an ''alarm clock'* chip. With proper 
interface to a speaker, it will generate a foud 
1 kHz beep at one second intervals until the 



D5 IN40D2 




o60Hy SAMPLE TO 
iC. PIN HQ.22 



■O + 9-I5V0C 
-9-15 VDC 



-9-15 VOLTS DC 

SEGMENT 

SEGMENTC 

SEGMENT B 

SEGMENT A 

AM/PM DATA 

50/60 Hi INPUT 

60 Hi .24 HR SELECT 

NC 
SNOOZE ALARMS 
ALAHW ACTIVATE 
ALARM OUTPUT 

NC 

ALARM/ACTUAL 
TIWE SELECT 




^-9-15 VOLTS DC 
SEGMENT E 
SEGMENT F 
SEGMENT© 

DJGIT6 
OlGfTS 

DIG IT 4 

DI6IT3 

DIGIT 2 

DIGIT I 

IIMTENSITV CONTROL 

DISPLAY ENABLE 

TENS MtNUTE SET 
HOURS SET 



BOTTOM VIEW 



Fig, 3, Power supply. 



Fig, 4. 50250 pin connections. 



AUGUST 1975 



97 



AM PM 



♦ 9-I5VO 



% 




Irio 



60 CPS 
INPUT 




spi en 

ALARM 
SPEAKER 




SNOOZE 
ALARM SET 



S3 



28 27 26 25 24 2 3 22 21 aO i9 18 17 f^ ii 

UL 
M0STEK-5025O 

t 2 3 4 5 & T B 9 10 I) 12 t3 t4 



I 




a 



S4 



^TIME 

fALARWMCTUALj 



I 



SB 



HOURS SET 



*- — lOMiN SET 



RK 
I5K 



Rl5 
1.5 K 



RI6 
I.5K 




I 



T 



♦ 9'I5V 



0Q000 



m 



Rir 

lOK 



SE 



SF 



SG 



m 



rn 



D5 



D4 



iff 



03 



^ 



m 



D2 



Dl 



/r? 



Fig, 5. ^Qhematic, 



alarm circuitry has been reset. The alarm 
operates in a 24 hour mode which ailows 
you to disable and Immediately re-enable the 
alarm to activate 24 hours later. Also built in 
is a snooze alarm for a period of 10 minutes 
upon which the alarm again sounds. The 
snooze alarm may be reset repeatedly at 10 
minute intervals. 









Mini chronometer readouts mounted in 
black plastic sheet. 



Fig. 3 illustrates the power supply re- 
quired to run the clock- T] is either a 
telephone transformer or a miniature 63 ac, 
500 mA filament transformer. Of course, the 
phone transformer is more convenient as it 
doubles as a wall plug. Di-Ds are 1N4002 
silicon rectifiers. Here, any 50 volt or more, 
1 Ampere silicon rectifier will suffice* An 
encapsulated bridge rectifier rated at the 
same is also convenient to replace D1-D4. 
D5, which acts as a half wave rectifier, 
provides the 60 cycle sample (clock) source 
For the IC. C2 may be 200 uF at 25 volts or 
more; 200 uF is just about the low limit for 
proper filtering. A 1000 uF or higher value 
may also be used. Depending on the trans- 
former used, (6 or 8 V ac) the dc output 
voltage should range anywhere from 75 to 
15 volts dc. 

Fig, 4 shows the pin connections of the 
50250. This is a bottom view with pins 
upward- 
Fig. 5 is the complete schematic with the 
exception of the readouts. The 50250 
emanates a positive pulse for activation of 
both digits and segments. Therefore NPN 
transistors were used to interface the 50250 
with the outside world. The I C by itself does 
not have the power handling capabilities to 
drive LED readouts directly, therefore 
higher power transistors must do the actual 



98 



73 MAGAZINE 





ior 10, IS, 20, 40 and BO METERS AMD THE COMPAMIOH 
MODEL 21s FOR 15 through 160 METERS. 




ATLAS 

RADIO INC. 






Measuring only 0.18 cu. H. and weighing less than 7 pounds, 
the Atlas 210/215 Solid Stale Single Sideband Transceiver is 
a real GIANT KILLER J t packs a hefty 200 watts P.E.R, offers 
5 band coverage, and unprecedented selectivity (only 9200 
cycles at 120 db down). 

Priced at just $599. it's the best transceiver value on the 
markel today. 




PERFECT CHOICE FOR 
THE ATLAS WHEN 
MOBILE 



STANDARD HUSTLER RESONATORS- 

Modei RM 10 . . . lU meter resonator 

Model RM 15 15 meter resonator 

Model RM-20 20 meter resonator 

Mode! RM 40 40 meter resonator 

Model RM 75 75 meter resonate. 

Model RM-80 80 meter resonator 

SUPER HUSTLER RESONATORS— Legal Power Limit 

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10 meter resonator 

.15 meter resonator 

20 meter resonator 

40 meter resonator 

... 75 meter resonator 
80 meter resonator 



Model 
Model 
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RM-IOS 
RM-15S 
RM-20S 
RM-40S 
RM-75S 
RM-80S 



TUFTS 



~^adio Electronics 



386 Main St., Medford, Mass. 02155 



; 




AUGUST 1975 



99 



*piia 



switching- All of the NPN switching tran- 
sistors used were those obtained from the 
Radio Shack Quad Pack (Part #276-530) 
and were NPN medium power general pur- 
pose. The snooze, hours set and 10 minute 
set switches are of the normally open type 
of push'button. 

The actual size printed circuit board 

shown in the figures can be photographically 
reproduced and made up; however, for a 
single clock, this process seems hardly 
necessary. We generally take a template such 

as this and cut a piece of PC board stock the 
same size. Scotch tape is then used to hold 
the template on the PC board, A sharp punch 
is used to indent the copper at all points 
where a hole is to be drilled or component 
inserted- When the pattern is removed, the 
punch marks will be in exact position. 
Ordinary finger nail polish and a fine brush 
are then used to '*paint between the dots'* 
and duplicate the original pattern. The nail 
polish dries very fast and is an excellent 
resist. The board is then placed in a heated 
ferric chloride solution which rapidly 
removes the excess copper. The nail polish 
resist is then removed with nail polish 




remover or **Stripeze" (paint remover). The 
initial punch marks now serve as center- 
punch guide holes when you drill all the 
holes (#56^60 drill). All necessary com- 
ponents with the exception of the power 
transformer and readouts are placed on this 
board. 

Fig* 7 shows where transistors and diodes 
are inserted on the PC board. Make sure you 

use the 50250 socket. It would be very 
difficult to remove a defective 28 pin IC 
should it be defective. The NPN Radio 
Shack transistors used do not .have the 
conventional lead connections as do normal 
garden variety transistors; therefore, we have 
illustrated where the "flaf side of the 
transistor is placed to correctly orient the 
leads. All parts are inserted from the non-foil 
side of the board. As you insert the com- 
ponents, solder them in place with a 25 Watt 
fine tip iron and trim off the excess leads 
close to the PC board. 

Fig, 8 illustrates the placement of the 
encapsulated rectifier bridge, as well as the 
resistors and capacitors. Individual 1N4002 
silicon diodes may be used, although the 
encapsulated bridge is a much more conven- 
ient device. The bridge we used was a 50 piv, 
1 Ampere unit which is also a Radio Shack 
device. The .005 capacitor is a small ceramic 
disc type rated at 50-100 volts. The 200 uF 
35 volt filter capacitor is small enough to be 
placed flat on the PC board, and polarity 
must be observed. Only one jumper is 



m 



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DS'ifV4oqg 




T Si DC «S 



60TT0W V<E# 



EMiTTEl^ 
BASE 



PAftrs iN£EirT£0FII0i*0^POStTr Si&€ 



Fig, 7, Transistor and diode placement Transistors 
are NPN, medium power from $1.98 Radio Shack 
Fig. 6. PC board (full size). Quad Pack ^76-530, 

Full size negatives for Fig. 6 are Qvailable for $2.00 each from PC NEGS, 73, Peterborough NH 03458. 

^^rt Order rhV2A00-l. 

100 73 MAGAZINE 



CHCAP-SULATED 



ALL10K- 



looa 




All 

L9M 







-'VW 



W«ITC DOT 
tNOtCATES 



-vwy — * 



fOK a lOQfJ RESISTORS 
ARE fNSERTED THRU 
aOARD "STANDING UP*' 




I5« RE51ST10RS «*VE 0«LT 
ONE SIPE TtfRU BOARD 



WIRE T9 
E400UT 



PARTS tNSEHTEtJ ^AOM Of'P'QSrflE SiCE 



CWlRe 
RE400IJ 



Fig. 8. Rectifier and resistor placement. 

necessary on the board and may be any 
snnall piece of copper wire. The 1 Ok resistors 
and the 100 Ohm resistors are inserted 
"standing up" so as to conserve space- The 
1/8 Watt resistors stand up about 1/2" high. 
The l-5k resistors also are inserted in the 
board "standing up" and soldered. The 
opposite end is trimmed off leaving about 
1/8" of lead on the resstor A wire gomg to 
the proper readout must be soldered to this 
standing resistor lead. This was used to 
conserve PC board space- To really conserve 
on space, the PC board may be cut off so 
that the encapsulated bridge and 200 uF 
capacitor are separate (with appropriate 
jumpers made up). This is necessary to 
squeeze the board into the 3" square cube, if 
these are your plans. 

Fig. 9 shows the external and time 
function control switch connections. The 
digit wires are soldered directlyto the board. 
All of the segment wires are attached to the 
top lead of the 1,5k resistors previously 
soldered in place. The 60 cps connection can 
either go to an external 60 cps frequency 
source such as a crystal frequency divider or 
to either of the ac points on the PC board 
for a 60 cps sample (jumper). The speaker 

terminal goes direcdy to an 8 Ohm minia- 
ture speaker and the other speaker connec- 
tion returns to ground or the edge foil of the 
PC board- Holes may be drifted in the corner 
section of the PC board for mounting it on 

standoffs. 

The opposite side of the lime function 
control switches is attached to the +9 -1 5 




SCfi"0" 

SES"*" O-^ww 

AM/PM LED 
60 CPS 



PUSHBUTTON 



REAL/ALAflM T1M(F 
SPEAICfW 




OSEC*E- 
^^'^ — OSEG'S' 

piaiT 1^ fi 

DlQlT MO 9 

-Dl&IT NO 4 

D^GIT NO. 3 
TEN MIM StT 
OIQIT NtJ 2 

DIGIT NO. I 
MOUftS SET 



FUi. ^.^L -t ^. --.O U^ 



Fig. 9. External and time function/control switch 

connections. 

volt lead. Refer to the main schematic (Fig. 
5) for the type of switch and connections. 

After you have wired and completed all 
the previous goodies no doubt you have had 
your bifocal prescription modified as well. 

Once power is applied, there are two 
possible things that will happen. The clock 
will either smoke and immediately burn up, 
or the numbers 12:00:00 will appear when 
the switch for real/alarm time is in either 
position. Luck is with you and the phases of 
the moon are correct if you obtain the 
12:00:00 reading. Don't let it frighten you if 
the seconds are not counting when first 
obtaining a display. Both the hours and ten 
minute push-button switches must be 
depressed simultaneously to begin the time- 
keeping function with the real time/alarm 
switch in the real time position. If there is 
leak over between digits, it means you have a 
transistor that has excessive leakage in your 
driver stages. It is quite common to find a 
'lemon" in the transistor drivers. 

Anyway, jt takes a bit of practice to get 
used to setting the clock with the hours and 
ten minute switches. Once you have become 
proficient at this, it is time to experiment 
with alarm. We should have mentioned 
previously that an anrvpm LED should have 
been attached as shown in Fig. 9- This may 
be any small LED connected to the am-pm 
transistor driven When the clock is in the am 
mode, this LED will illuminate. The main 
purpose of this LED is to allow you to set 
the alarm function properly. If you place the 
alarm/real time switch in the alarm position, 



AUGUST 1975 



101 






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Frequency Standards 

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1000 KHz {HC 6/U) 4.50 

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2400 Crystat Df . Ft Myers. Fla 33901 
All Phones (813*936 2397 

Send 10 'or new catalog with 12 
oscillator circuits and lists ol 
frequencies in stock 



CRYSTIllS 



the LED will come on if you desire am alarm 
settings. The same switches used to set the 
alarm time are used to set the real time- 
When the alarm enable switch is in the 
enable position, the alarm will sound with a 
loud one second beep when the real time has 
reached the alarm set time. The snooze 
alarm switch, if depressed when the alarm 
goes off^ wil! allow 10 minutes of silence 
before the alarm sounds again. This may be 
repeated indefinitely until the alarm enable 
switch is shut off. If you wish, this feature 
may be incorporated as a 10 minute timer 
for station indentification. 

With the alarm system, there are two 
charactenstics that should be avoided* The 
alarm should not be exactly set at 1 2:00 am 
or 1 2:00 pm or 8:00 am or 8:00 pm. Setting 
the alarm a few minutes before or after these 
times will allow reliable operation. 

Should the local line power drop below a 
usable level, the am/pm LED will blink at a 
1 cycle rate. This tells you the clock has lost 
time or needs to be reset correctly. 

This clock should be an interesting pro- 
ject to construct and will serve you well At 



9 




Bottom view of mini chronometer, showing 
time set push-buttons and alarm/real time 

switches, 

the very least, it will give you considerable 
insight into the functions of large scale 
integrated circuits and their capabi lilies. The 
state of the art in electronics is no further 
away than the tip of your soldering iron (25 
Watt fine tip). 

Parts List 
Fig. 3, 

CI - .002 uF 100 V capacitor 
C2- 200 uF {or higher) 

D1-DS — 1 N4002 silicon diodes. A single encapsu- 
lated bridge (50 V @ 1 A) works well also, 
Fl — 1 A 1 25 V sf ow blow fuse 
Tl — Plug in Princess telephone transformer, 6-8 V 
ac, 1.75 VA secondary, 117 ac primarv (or 6,3 ac 
500 mA filament transformer) 

Ftg- 5, 

Q1-Q15 - Radio Shack (Archer) ^76-530 tran- 
sister quad pack ($1.98), Use the NPN medium 
power general purpose transistors (6 per pack). 
There are 24 transistors (assorted) in each pack, 
the remainder of which make good spares, etc. 
R1-R5, R14-R16 - 1/8 Watt, 1500 Ohm carbon 
resistors 

R6-R10 - 1/8 Watt, 10,000 Ohm carbon resistors 
R18 « Vs Watt, 1 00 Ohm carbon resistor 

51, S4, S5 — Normally open miniature push-button 
switches 

52, S3 — Single pole miniature toggle switches 
SP1 — 8 Ohm 2 in- speaker 

U1 - Radio Shack #276-1751 MOS-LSI Digital 

Alarm Clock IC 

, , ,W2A00 



102 



73 MAGAZINE 



73 Magazine Staff 



An Accessory VFO 

Easy Way 




Most amateurs who use an HF trans- 
ceiver at times desire having an acces- 
sory VFO for separate VFO control of the 
transmitting and receiving frequencies. If the 
transceiver does not have receiver incre- 
mental tuning, the addition of an accessory 
VFO becomes an even more desirable item. 
Accessory VFO*s can be purchased for most 
transceivers, of course, but their cost can be 
a considerable fraction of the original cost of 
the transceiver since the accessory VFO 
usually duplicates the stability, housing and 
frequency scale readout of the transceiver's 
VFO, 

The accessory VFO circuits described in 
this article can be developed into full-scale 
accessory VFO's but there is another possi- 
ble use for them v^tth a transceiver u^hich 
requires far less work and yet provides most 
of the advantages of a regular accessory 
VFO, As was just mentioned, most regular 
accessory VFO's duplicate the transceiver 




zeno-BEAT 



MIXER 



Tk 1-2 pF 



R}^ 




B^EAK 
CONNCCTrON 

O K- 



y^< 



TRANSMIT 



ACCESSORY 
VFO 



yPO S^AflTCHOVfR 
IN TnANSC£lV£R 



fRANSCEtVER 
VFO 



TRANSMITTER 
CIRCUJTS 



Fig. 1. Bbsic use of accessory VFO. 



VFO and one can use the transceiver or 
accessory VFO interchangeably since they 
both have the same frequency calibration 
scales. Another approach to the use of an 
accessory VFO would be to tune the trans- 
ceiver (using the transceiver VFO) to a 
desired transmitting frequency, switch on an 
accessory VFO which can be zero-beated to 
the transceiver's VFO frequency and then 
switch VFO control of the transceiver in the 
transmit mode to the accessory VFO. In the 
receive mode the frequency control of the 
transceiver would remain with the trans- 
ceiver VFO and could, of course, be tuned as 
desired- This scheme requires only the use of 
a stable, external VFO without elaborate 
frequency readout, which can be zero-beat 
with the transceiver VFO and which can be 
switched in the transceiver to assume fre- 
quency control of the transceiver during 
transmit periods. The circuitry to do the 
latter is already provided in any transceiver 
which has provisions for the use of an 
accessory VFO. To zero-beat the external 
VFO with the transceiver VFO, the external 
VFO signal is introduced to the transceiver 
in the receive mode as though it were a 
regular received signal, and the external VFO 
tuned for zero-beat > With most transceivers 
the level of an external VFO is usually great 
enough so it can be introduced at the 
antenna terminals of the transceiver and not 
be severely affected by the selectivity of the 



Alim |<^T 1Q7R 



t03 




Operate Auto-Patch 

use antenna and power . . . The GTX-200-T does 

all the rest! 

The 12-digit tone encoder is an integeral part of the 
2-meter VHF-FM transceiver (WOW!) Separate controls 

allow independent transmit and receiver frequency selec- 
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The GTX-200-T is all solid state, transmits at 30 watts 
(nom,), also features super-sensitive dual-gate MOS FET 
preamp receiver. Same old GTX-200 — but what an 
addition! 



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and signal output, and it's ready to operate. 

The TE-II produces all standard double frequency tones 
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n PSI-11 Battery Pack (with charger) 

Q ARX-2 2-M Base Antenna 

n Lanibda/4 2-M Trunk Antenna 

Q TE-I Tone Encoder Pad 

Q TE-II Tone Encoder Pad 

G PSI-9 Port. Power Package (less batteries) 

Q PS-1 AC Power Supply 

and the following standard crystals @ $4.50 each: 
Non-standard crystals @ $6.50 each: , 

(altow 6 weaks delivery.) 



@ $109.95 $- 

$49.95 $- 
$69.95 $- 






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Far factory crystaf mstalfation add $8.50 per transceiver. 

IN residents add 4% sales tax: 
CA residents add 6% sales tax: 

All orders shipped post-paid within contir}er}tai U.S. 
NAME 



Sub-Total: $. 
TOTAL: $, 



(minimum order $12.00} 



PHONE 



AMATEUR CALL 



ADDRESS. 



CITY. 



STATE & ZIP. 



Payment by: □ Certified Check/Money Order □ Personal Check n CO. D. Include 

Note: Orders accompanied by personal checks will require about two weei<s to process. tO^ Uown, 

n 20% Down Payment Enclosed. Charge Balance To: 

n BankAmericard # Expires 

□ Master Charge #_ ^ Expires Interbank # 



I Prices and specifications subject to change without notice. 



m 



i 



.OOl5 
M 

365 



T 1 

—I— dnAM — 1— 






4Q0N 
750 



/77 



001 



m 



.0025 




/fl 



22 



2NE&7I 



IK 




220 



-a4v 



20V 



tOK 




aht267l 



OJ 



OUT 



4,7K 



Fig. 2, An old fashioned (PNP transistors J but extremely stable VFO, Bs^ic osdllator frequency is 5 

MHz with about a 250 kHz tuning range. Capacitors marked "M" must he silver mica type. 



circuits in the rf amplifier stage* So, it can be 
used to zero-beat with the transceiver VFO, 
If, however^ an effective zero-beat cannot 
be obtained, the external VFO signal can be 
introduced directly to the input of the mixer 
stage which the transceiver VFO also feeds. 
The amount of the coupling required is 
usually very light and can be effected via a 
simple 5 to 10 pF capacitor coupling from 
the externa! VFO* This method will work 
with any transceiver where single conversion 
is used, such as the usual 9 MHz i-f trans- 
ceiver. Unfortunately, it is not possible to 
present the VFO switching circuits available 
in every transceiver but if the general switch- 
ing idea outlined is followed and experi- 
mented with, there should be no difficulty 
in making a satisfactory connection to one 
of the VFO circuits to be described- 
Fig. 1 Illustrates the transceiver switching 
idea involved. The rest of this article des- 
cribes several circuits suitable for external 
VFO usage. Each is quite stable and can be 
adapted to work over any of the ranges 
suited to an HF transceiver — namely, a 250 
to 600 kHz range within any selected por- 
tion from about 4 MHz to 12 MHz, The 
various circuits have their own advantages 
and disadvantages depending both upon 
what components one already has available 
and on the tuning method desired. 

Fig. 2 illustrates a rather old fashioned 
VFO, in a sense, since PNP transistors are 
used. But, it is an extremely simple and 
stable circuit. The tuning range is about 250 
kHz in any segment of the 5 to 9 MHz range 
depending upon how the oscillator coil is 
set. It is a high — C type circuit and so the 
oscillator coil is relatively small in value. The 
coil, however, should be wound on a ceramic 
coil form or be an air-wound coil. The 
capacitors noted in the circuit must be mica 



types to ensure stability. The tuning capa- 
citor is a very easy to obtain 365 pF AM 
radio tuning variable. The 400/N750 temper- 
ature compensating capacitor shown is not 
absolutely necessary and may be a difficult 
component to obtain although it is not 
expensive. It can be replaced by a regular 
400 pF mica capacitor* The only instance in 
which this capacitor is necessary is if the 
VFO is to be used in a mobile application- In 
that case, it should be placed near the VFO 
coil to achieve maximum temperature 
stability of the oscillator. A positive supply 
voltage could be used by grounding of the 
collector circuit and feeding the positive 
supply voltage via the emitter resistors of 
each transistor. Because of the high capaci- 
tance loading on the oscillator tank circuit, 
the 365 pF tuning capacitor need not be 
located directly adjacent to the VFO. It can 
be coupled to the VFO via a short length of 
shielded cable (RG174) if this is more 
convenient in a given transceiver. 

The circuit of Fig* 3 is a bit more 
conventional in that it operates from a 
positive 12 volt dc source* The VFO coil is 
air-wound and consists of 17 turns of #18 
wire, 5/8" in diameter, or the B&W coil stock 



.001 



^f 



M 




NO 18 
5/8 ill. OIA 




*\2 



.001 ■' 

7^680 ;if 220 :if 

^r Jj^ J? MAIN ^ 1 
018 rUNE 



OUT 



Hg. 3* This osciilator tunes about 500 kHz starting 
at 5 MHz. Only three silver mica capacitors are 
required. 



106 



73 MAGAZINE 



equivalent. The osciHator operates at about 
5 MHz with the main tuning control cover- 
ing a 500 kHz range and the fine tuning 
control covering a ± 20 kHz range. The 
oscillator can be made to operate over 
almost any position of the HF range by 
proper selection of the coil. Note that mica 
capacitors must be used for the two .00 1 uF 
and one 680 pF capacitors associated with 
the oscillator coil. The output at the emitter 
coupling capacitor of the buffer stage is a 
relatively high 4 volts peak-to-peak. 

The circuit of Fig. 4 is extremely inter- 
esting in that it requires no tuning capacitors 

(and no varactor diodes) and provides tuning 
over a small tuning range (about 50 kHz 
centered on 7 MHz). It would be very 
suitable for someone interested in operation 
over a particular portion (CW or phone) of 
one band. Although there are no varactor 
diodes in the circuit, as such, the collector to 
base junctions of the two 2N3053 transistors 
perform the same function. The circuit 
requires a minimum of critical components- 
Only the three capacitors marked as being 
**M" must be of the silver mica type* If one 
wanted to considerably expand the fre- 
quency ban dsp read of the oscillator (to 
about ± 250 kHz about the center fre- 
quency), the 1 30 pF '*M*' capacitor could be 
replaced by an air variable and the potentio- 
meter tuning still be retained for fine tuning. 
This modification would not change the very 
good basic frequency stability of the oscill- 
ator and only two silver mica capacitors (50 
and 380 pF) would be required for the 
whole oscillator circuit. 

Fig. 5 is another oscillator circuit that has 
been widely used, especially in QST articles. 
It is the same type of oscillator as the 
preceding one but includes an emitter 
follower buffer stage for isolation. The 
emitter follower stage contains a low pass 



2 N 3053 



MILLER 
4404 ^T7 




_1_I30 -^50 



M 



^^ 



OUT 



2N363a 



M 



^380 

Tm «2 2K 



■^ tOOK ^ 
TUMtNG 




♦12 



6. S K 



Fig, 4. This interesting VFO tunes only about 50 
kHz starting from 7 MHz. It can be modified for 
greater range, 

filter to reduce harmonic output and pro- 
duce a better sine wave output waveform. It 
is not really necessary if the VFO is to be 
used for transmitting control only. The 
oscillator coil should be enclosed in a shield 
at least twice as wide as the oscillator coil 
diameter. Such a shield can be assembled by 
soldering together pieces of copper clad 
circuit board. With the components shown, 
this oscillator tunes from about 4000 to 
4600 kHz. It can, of course, be modified to 
cover other frequency ranges- If one wanted 
to try the oscillator without the buffer stage, 
the 33 pF mica should be connected instead 
to the junction of the two 1,000 pF mica 
capacitors and the output taken from this 
pornt 

This article presents a variety of oscillator 
circuits to be used as a transmitting control 
VFO in the manner described- Each of the 
circuits has been tried and proven. The main 
precautions to be used in the construction*of 
any oscillator is to use a good quality, rigid 
oscillator coil (cemented air core or wound 
on a ceramic form) and to use silver mica 
capacitors at the locations specified. Styro- 
flex capacitors may be used as substitutes 
but never disc ceramic types. If the VFO is 
used to zero-beat with the transceiver VFO, 



X 



or 




«40 
TUNrNG 



33 
M 



^[ 



4503 




220 



*I2 



9tV 



53 
-)! OOUT 



2 TO 



/77 



Fig, 5. This oscillator tunes over about a 500 kHz range. Both transistors are HEP 53. 



AUGUST 1 975 



107 



-WE GOT 'EM - 

CLEGG, COLLINS, DRAKE, 
SWAN, YAESU, TEN-TEC, and 
many more in stock. Large selec- 
tion of used equipment See us for 
quick courteous service. Established 
7928. 

FRECK RADIO & SUPPLY CO. Inc. 

P.O. Box 7287 W4WL 
As/ievil/e NC 28802 



BANKAMFRICAR'D 



if'tf/ffm fir 



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iiiiislrif iMnw 



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FM Modulation Meter 

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with earphone SI 2.95 

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Jndiana residents add 4% sales laR. Cfyitate for 146.94 MM? $3 95 

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412 North Weinb^cti Ave. 

Evjn&vtt}«, IndtatiA 47? Li 

S12-476'2121 



a frequency readout scale on the accessory 
VFO is not really required once one is sure 
of its frequency range. Construction can, 
therefore, be extremely compact in any 
form of shielded enclosure. 

The last point to check is that the 
accessory VFO has sufficient output level. 
One should, of course, check the VFO 
output level necessary with a transceiver 
before building the accessory VFO. Most of 
the oscillator circuits shown will provide 
several volts peak-to-peak output and should 
suffice for almost any requirement If the 
oscillator is to be used only for transmitting 
control as described, the criterion for proper 
oscillator output is quite simple. The trans- 
mitter output level and signal quality should 
be the same as when the transceiver VFO is 
used for frequency control in the transmit 
mode. These qualities are fortunately quite 
simple to check using the transceiver's 
meters and on-the-air checks. The situation 
in checking such a VFO for receiving control 
is far more difficult to evaluate and usually 
demands a good array of test equipment 

,-. STAFF 





-stirr=? 



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Radio Co., Inc. 

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216) 426-8073 




108 



73 IVIAGAZINE 



Compatible with all sub-audible tone systems such as: Private Line, 
Channel Guard, Quiet Channel, etc. 

• Powered by 6-16vdc, unregulated 
Microminiature in size to fit inside all mobile units 
and most portable units 

jField replaceable, pitrg-in, frequency determining elements 
'^ ""^ ' Irfi^tu ^ g/ accuracy and temperature stabtiltv J 

M adpRnent potentiometer j 

i^W distofjtoriffinewave output ! 

^ajvaitatyre- m Mb^ 1 A tone frequencies, 67.0 Hz^203.5 Hz 



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otection built-in 



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AUGUST 1975 



109 



Tmn/Kriv about 



paw It AWPIIFiH 



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2 METER SSB/CW 



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10 Watts PEP output 

Complete with microphone, two 

power cords 8e mobile mounting 

bracket 



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Options now available for ECHO II 

• USB/LSB mod kit for reception of 
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• LOW NOISE (2.5db nf typ.) preamp 



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Gain 9.5 dbd 

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WINNER 1975 UHF WEST COAST 
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NEW... KLM 432-16 LB 15 dbd 16 
ele. yagi for 430-434 MHz complete 
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Write for complete catalog or contact your local KLM DEALER (see June 73 
Magazine for COMPLETE LIST) 



1600 Decker Avenue, San Martin CA 95046 (408) 683-4240/226-1780 



no 



73 MAGAZINE 



Eric K. Albrecht K8BFH/1 
c/o 73 Magazine 
Peterborough NH 034 58 



Modem Nan -Morse Codes 



Like ASCII and such 



Digital information may be in the form 
of individual on-off signals, or it may 
be encoded. And if encoded^ it may be serial 
or paralleL The serial format consists of 
various bits of information in one place at 
different times, and parallel has the various 
bits in several places at the same time. For 
example, a RTTY signal is serial, a series of 
pulses in order. Within the machine, the 
information is converted from electrical to 
mechanical information, in a parallel format 
Punched tape is a parallel format as well 
(bit-wise anyway; complete characters are 
arranged In a series). 

There are a number of encoding schemes 
of interest to amateurs, the first of which is 
Morse. This is generally found in serial form 
only, but these days not always. Others are 
Baudot, the old five-untt- plus-con text tele- 
typewriter code, and the American Standard 
Code for Information Interchange (ASCII), 
eight-unit, or seven-plus-parity actually, also 
used for TTY and computers as well. This 
pretty well takes care of the Major Leagues. 
There are other codes used for computers, 
notably EBCDIC (Extended Binary Coded 
Decimal Intercommunication Code), IBM's 
favorite; Univac*s entry, Fieldata; Hollerith 
(used on punch cards but almost nowhere 
else — the punch card was invented by Mr. 
Hollerith in the late 19th Century and exists 
today basically unchanged except for the 
addition of numerous characters, including 
my favorite, the lozenge); TTS (teletypeset), 



a six-bit version of Baudot used, as its name 
implies, in typesetting, with or without 
computers; and the Friden Flexowriter code. 
These also belong in the Majors, but are not 
generally of interest to hams. 

The Minors include BCD, Gray, XS3, XS3 
Gray, Touch-Tone, MFKP (Multi-Frequency 
Key Pulse, the operator *s Touch-Tone), 
2-4-2-1, biquinary, straight binary and its 
alter egos octal and hexadecimal. These are 
all simple systems which basically represent 
only numbers. In the case of MFKP there are 
two extra combinations representing the 
start of a sequence, called KP, and the end, 
called Start. And TT has asterisk (*) and 
hash mark (#) and four nameless com- 
binations. 

Then there are the bush leagues — an 
endless variety of possibilities, tailored to 
the applications. Any time you have more 
information than wires, and sometimes even 
when you don't, you have a code. Without 
encoding, for example, 10 wires can embody 
20 functions in pairs, such as on-off, 
up-down, etc* This has the advantage that all 
of them are completely independent — or 

sometimes the disadvantage- But encoding 
gives those same 10 wires a maximum 
capacity of 1024 functions, or 2^^ instead 
of 2 X 10. This does not mean that you have 
to lose any sleep over some of those possi- 
bilities going to waste, and often unused 
combinations provide elbow room, making it 



AUGUST 1975 



m 



easier to work with a code scheme. Of 
course^ now that we have implemented a 
code, the whole system can represent only 
one function at a time* If this is a problem, 
the information can be partially encoded, 
with various subgroups of bits assigned to 
various functions of groups of functions, 
while the whole 10 (or whatever) bits can be 
used for others. You can even make the 
subgroups (called bytes) talk to each other — 
such as carry or borrow signals when per- 
forming arithmetic functions in a calculator 
circuity or override signals for shutting down 
the carcinotron when the klaveman goes 
south. 

Definitions 

Before going any further, 1 ought to 
define some terms I have already used. 

Context: In the Baudot code, two of the 
32 possible combinations of five bits are 
assigned to shift between two sets of mean- 
ings for most of the rest of the code. When a 
Shift or Unshift character is received, it is 
stored, either mechanically or electrically, 
and must be considered when deciding what 
the subsequent code combinations mean. A 
particular combination means either the 

letter Y or the numeral 6, and you can look 
at it all night and not know, unless you 

know the context in which it was sent Of 
course you can take a whole line without 
shifts (and sometimes you have to), try it 
both ways and see which way it makes sense^ 
but that is just a more complex way of 
an-iving at the same information. You still 
have in any given character five bits of text 
and one of context; almost like six for the 
price of five, but it helps to at least say so 
each time you change from one context to 
the other. TTS, meanwhile, sends all six and 
uses shifts to expand the code, to handle 
lower case letters and functions peculiar to 
typesetting. 

Parity: In ASCII and several other codes, 
an extra bit is included to check for errors, 
and sometimes several bits are added (more 
about that later). It is much more likely that 
a noise burst will clobber one bit than two, 
so all the information bits are added up, and 
a parity bit is added so that the total number 
of *'on*' or "1" bits will be even, or odd, 
depending on the system — but once estab- 



lished, it does not change. If the system is 

Even Parity and a character whose info bits 

are 1101100 is to be sent, a zero bit is 

tacked onto the end, giving 11011000, If the 

next one is 1 001 111, that's odd, so we add a 

1 and get 1 001 1111, which is even. This is a 

simple error-checking system, and it is 

possible for multiple errors to sneak 

through, as long as they alter an even 

number of bits. But a noisy circuit wit! show 

its hand pretty quickly anyway. 

Binary: There are actually two slightly 

different meanings floating around. 

Generally it refers to a number system or 
representational system, each element of 

which can be in one of two states. The states 
can be called mark and space, one and zero, 
high and low, true and false, A and S (not 
-A), or even Mark and Fred. Whatever you 
call them, as long as there are two of them, 
it is binary* A code can be binary while 
having little or nothing to do with numbers 
— ASCII is a binary code, even though only 
10 of the 128 combinations represent 
numbers. The other shade of meaning is 
specifically the base 2 number system, where 
the digits are 1 or 0, where a 1 has a 
numerical value of some power of 2, When- 
ever there is a possibility for confusion, you 
can add a word, and say straight binary or 
something like that to indicate the second 
meaning. 

Octal: This is binary in disguise, and 
consists of using the base 8 system, with the 
digits 0-7, as a shorthand to indicate three- 
bit groups of binary, 000 through 111. 
Programming languages such as Fortran 
allow for using octal representation any- 
where desired, when indicated by sticking a 
leading zero on the number. Thus 0427 = 
4278 ^ 100 010 1112. (Subscripts are not 
available on a TTY.) Similarly, I often use a 
pair (or more) of leading zeros to indicate 
base Z So 010 - 1 08 - 8l0; 001 - 102 = 2; 
but 10 = ? When the scratch pad gets fullj it 
helps to have some indication. 

Hexadecimal (''Hex''): This is another 

disguise like octal, but bits are grouped in 

fours, giving sixteen combinations. The 

digits 0-9 are used, and the letters A-F; e.g. 

Ai6 = IOIO2 = lOiO- Neither octal nor hex 
has any effect on the binary code itself, 

BCD: This stands for binary coded de- 



112 



73 MAGAZINE 



e's i6's 



GRAY 



BfNARY 



GRAY 





BINARY 

-»-♦ 




CLOCK-* 




GRAY 



Efg. 1- A) Parallel: Gray to binary to Gray (for 
XS3 - XS3 Gray, delete one gate); B) Serial (most 
significant bit first )» 

cimaL Any number can be expressed in any 
format, and they all have their advantages. 
Straight binary is most suited to the internal 
working of computers, but it's harder for 
humans to use than decimal. BCD groups the 
bits in fours, and the first group on the right 
represents the same value in hex, namely 
8-4-2-1, but the largest number represented 
is 9, with the six remaining combinations 
defined as meaningless. Thus 0101 - 5, but 
1101 = error. The tens digit of a decimal 
number is represented by another group of 
four bits with the values 80-40-20-10, and so 
on. So 0101 0000 then means 50, and 73 
comes out as 01 11 0011, 

Some other decimal/binary crossbreeds 
are 2-4-2-1 and biquinary {5-4-2-1). The 



latter gives a symmetrical cycle in the most 
significant bit, and some decimal counters, 
such as the 7490, can be connected for this 
code output or for BCD, as desired. 

Gray code: This is a modified binary code 
having only one bit changing at a time when 
going from one number value to the next 
higher or lower. If you wish to encode the 
position of a shaft, for instance^ BCD and 
binary have serious 'drawbacks- In either 

base, for instance, changing from 7 to 8, 
0111 to 1000, has four bits changing at 
once. The changes will never be truly simul- 
taneous, making errors just about inevitable- 
If only one bit changes at a time, the only 
possible outputs are the two codes on either 
side of the transitions, 

XS3 (ExcesS'3): This is BCD code except 
that the literal value of the code is offset +3 
counts. This is useful in decimal arithmetic, 
since the inversion (trading Vs for O's) of 
any number produces the nines complement 
of that number (9-n), greatly simplifying 
subtraction, 

XS3 Gray: Decimal position encoding 
with regular Gray code would have a three- 
bit transition between and 9, but XS3 
Gray has only a one-bit jump there. Con- 
version to BCD involves two steps: first to 
XS3 with a string of exclusive-or gates {if 
parallel format) or a JK flip flop {serial); 
then from XS3 to BCD by subtracting 3 



Decimal 



Binary 



Octal 



Hex 



BCD 



XS3 



XS3 Gray 



Gray 






0000 








0000 


0011 


0010 


0000 


1 


0001 


1 


1 


0001 


0100 


0110 


0001 


2 


0010 


2 


2 


0010 


0101 


0111 


0011 


3 


0011 


3 


3 


0011 


0110 


0101 


0010 


4 


0100 


4 


4 


0100 


0111 


0100 


Olio 


5 


0101 


5 


5 


0101 


1000 


1100 


0111 


6 


0110 


6 


6 


0110 


1001 


1101 


0101 


7 


0111 


7 


7 


0111 


1010 


nil 


0100 


8 


1000 


30 


8 


1000 


1011 


1110 


1100 


9 


1001 


11 


g 


1001 


1100 


1010 


1101 


10 


1010 


12 


A 


- — -*- 


-_.-^ 


-^^^ 


1111 


11 


1011 


etc. 


B 








mo 


12 


1100 




C 




etc. 




1010 


13 


1101 













1011 


14 


1110 




E 








1001 


15 


nil 




F 




> 




1000 


16 


10000 




10 








11000 


17 


10001 




11 








11001 


18 


10010 




12 








11011 


etc. 


etc. 




etc. 








etc. 



Table L 



AUGUST 1975 



113 



(another whole subject). Gray to binary 
conversion is the same as the first step here* 
Binary to Gray or XS3 to XS3 Gray uses the 
same parts with different connections, 

BCD is a weighted code, meaning that a 1 
in any given position always has the same 
numerical value, or weight- Gray is a non- 
weighted code; an individual bit does not 
have a value by itself, but the whole group 
of bits does. 

In addition to the codes themselves, there 

are transmission schemes (though they are 

sometimes also called codes) with a lot of 

strange terms. Starting with the standard 

RTTY signal for illustration, this could be 

described as an alphanumeric code (letters 

and numbers), serial asynchronous (also 

called start-stop; a zero bit is sent for a start 

signal and a 1 bit for stop; timing is 

suspended between the stop and the next 

start), NRZ, or Non-Re turn-to-Zero, which 

means that if a pulse is a 1 , or mark, it stays 

there until the next pulse (which will keep it 

there if it's a mark too). The opposite of 

asynchronous is synchronous, where start 

and stop signals are not used. Instead the 

timing is continuous, and at the receiving 

end the timing information is recovered 

from the indivudal transitions- The idling 

condition, instead of a steady mark, must 

have some code character present to preserve 

the synchronization, and in ASCII a 

character called SYN, synchronous idle, is 

provided. 

In RZ (Return-to- Zero), encoding timing 

is again extracted from the individual bits, 
and each bit contains both space-mark and 
mark-space transitions. The transition to 
mark occurs at the beginning of the bit, and 
for a 1 it stays marking for most of the 
bit-time, but for a it goes quickly back to 
space and stays there for the rest of the 
interval- RZ has the disadvantage of re- 
quiring increased bandwidth as each info bit 
is accompanied by an explicit timing bit; 
that's one for the price of two. 

NRZI (I for Inverted) does not assign a 
mark as 1 and a space as 0, but instead 
defines a change (inversion), either mark- 
space or space-mark, as 0, and a steady state 
as 1 . "No data'* can be represented as steady 
null characters (all zeroes) without loss of 
timing since a string of 0*s is a string of 



transitions. But obviously a limit must be 
placed on the number of 1 *s allowed in 
succession. IBM's Synchronous Data Link 
Control (SDLC) system has a clever way of 
handling this, and though the system itself 
might not be too useful to the average ham, 
I think it is interesting enough to give a short 
description. 

SDLC is used when a network consists of 
a number of "satellite" (not to be confused 
with the ones in the sky) synchronous 
machines, terminals, whatever, and one 
master device which is in charge of the 
network. The master can talk to any of the 
satellites, and the satellites can talk only to 
the master, even though they are all on a 
party line. If station A has a message for 
station B, the master can tell B to listen in, 
or can retransmit to B. It doesn't matter, 
though; this is up to the designer of the 
individual system and not of interest to 
SDLC 

SDLC uses NRZI encoding, and allows a 

maximum of five Vs in a row, except for 
one special character called a flag, which has 

six. Any time the information you wish to 
transmit has five Vs in a row, a zero is 
inserted and then removed at the other end. 
If you have 111110, you send 1 1 1 1 1 00, and 
the other end knows that this means 
111110, The flag consists of 01 111 1 1 and 
is the only exception to this rule. Any 
transmission starts with a flag and ends with 
a flag. The idling condition between trans- 
missions is a series of flags. Bit timing is 
recovered, as mentioned before, from the 
O's, and character timing is started from the 
flags and maintained from the bit timing. 

The first non-flag characters sent are 
address and control fields of fixed lengths. 
The control field is a code entirely indepen- 
dent of whatever codes are used in the text 
of the message- The address field designates 
the satellite involved: If the master is 
sending, it tells who is supposed to be paying 
attention; if the satellite is sending, it tells 
which one- Assuming that the master knov« 
whether it is talking or listening, and given 
the constraint that satellites do not talk to 
each other, this is sufficient. 

After these fixed-length fields, we have 
the information field, or the text. This may 
be in any code you like, and any length, 



114 



73 MAGAZINE 



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AUGUST 1975 



115 



even empty. The only restriction is the five 
Vs aile, which is not really a restriction at 
all since it has no effect on the data 
conveyed. Next comes a parity (error- 
checking) field: fixed length, except it too is 
subject to the Rule- Last comes the flag, at 
which time the location of the parity field 
and the end of the info field are revealed by 
counting back a fixed number of bits from 
the flag- 

ErrorDetecting and Error-Correcting Codes 

Parity bits as provided in ASCII and 
blocks of parity information as in SDLC 
provide a means for detecting errors, but it is 
possible to add more redundant information 
and not only detect errors, but correct most 
of them as we!L No system can be totally 
foolproof, though, and there are diminishing 
returns from trying to make it so, as the 
efficiency of a system drops when you add 
the redundant bits needed to detect or 
correct errors. For amateur use, a message 
can just be repeated if received in damaged 
condition, but some systems have to get it 
ri^t the first time. For them, insurance is 
available in the form of additional redun- 
dundancy. While a single parity bit can 
always catch a single error^ it does not 
contain enough information to reliably 
detect multiple errors, and it cannot correcf 
errors at all. But error-correcting codes, 
called Hamming codes(!} are fairly easy to 
implement (though at least at present not 
legal for hamming). Such a code will always 
detect a double error^ and will always 
correct a single error. It is available in the 
following standard-sized packages: 



Data 
bits 

4 
11 
26 



Hamming 
bits 

3 

4 
5 
etc. 



Overall 
parity 

1 
1 
1 



Total 
bits 

8 
16 
32 



A Hamming code with overall parity con- 
tains 2^ bits; n is the number of Hamming 
bits, and there are 2^-n-l data bits. The 
longer the code, the more efficient it is (in 
data bits as % of total), though at the same 
time it is more susceptible to error. 

With three Hamming bits there are a total 
of eight combinations. One of them is 



assigned to mean "no error'\ and the other 
seven correspond to a detected error in one 
of the seven bits (4 info + 3 Hamming bits). 
The code is arranged so that the numeric 
value of the combination is the actual 
location of the error — even if the error is in 
one of the Hamming bits itself. If a double 
error were received, however, this system by 
itself would correct the wrong error. Addi- 
tion of the overall parity takes care of this; 
double errors still cannot be corrected, but 
at least they can reliably be detected. If 
overall parity comes out wrong and the error 
address is zero, then either there is a single 
error in the overall parity itself, or a double 
error, not correctable. The character is 
rejected. If overall parity is right and error 
address is not zero, a double error occurred. 
But if overall parity is wrong and the error 
address is not zero, there was a single error 
which can be corrected. Further discussion 
of error correcting codes is available else- 
whereJ'2 

Code Conversion 

With all these codes flying around there is 
often a need to convert from one to another. 
One way which will work with any codes is 
to use a Read-Only Memory (ROM) which 
simply consists of a cross-reference table* If 
the ROM is large enough, several codes can 
be accommodated in it, and it is possible to 
make one device which will handle, for 
instance, ASCII, Baudot, Morse, Touch- 
Tone, and turning on the coffee pot on your 
way home- 
Any binary code, whether weighted or 
not, can be easily converted to 1-of-ji no- 
tation with chips like the 7442, a 1-of-lO 
decoder. This one takes a BCD input and 
produces a "low*' on one of ten output lines, 
corresponding to the value of the Input 
code. Alt other output lines remain high. If 
the input code has a value greater than 9 
(defined as bogus in BCD), all output lines 
are high. Similar 1-of-lO chips are available 
for XS3 (7443) and XS3 Gray (7444). There 
are also l-of-16 decoders, l-of-S, and dual 
lof-4- The latter has two independent de- 

Error Correcting Codes^ Peterson and Weldon, 
MIT Prpss, Cambridgev 1972. 

Applications Manuals irom various IC manu- 
facturers. My favorite is Fairchild. 



116 



73 MAGAZtNE 



coder circuits in one chip. AH of these will 
work with any code; 1-of-lO requires special 
chips for special codes since, for instance, 
some of the combinations in XS3 Gray are 
wrong numbers in BCD, and vice versa. One 
of the main limitations in chip design is the 
number of output leads available, but a 
nmitation in amateur design is the the parts 
available* You can use a 7442 as a 1 -of-8, or 
two of them as l-of-16, and so on. Different 
codes are handled by redefining the outputs. 
In the same way, by arranging the inputs 
and outputs, a chip like the Fairchild 9318 
Priority Encoder can be used to encode 
l-of-8 or multiples thereof into any code. 

Only one input can be encoded at a time, 
and this chip produces output code cor- 
responding to the highest-numbered active 
input if there are more than one. For some 
applications this is quite handy, while for 
others it is necessary to bypass this feature 
by ensuring that there is actually only one 
active input at a time. There must be 
thousands of ways to use this chip. 

A code converter can be made from 
decoder and encoder chips very easily. This 
is most suited to the situation where either 
the Input or the output code, or both, is 
oddball, which includes alphanumeric codes. 
ASCI I /Baudot/Morse can be handled this 
way. Each input code requires a set of 
decoders (and only one may be active at a 
time) and each output code takes a set of 
encoders. All output codes are available 
simultaneously without switching. If there 
are several input codes, open-collector de- 
coders should be used, such as the 7445 in 
place of the 7442, an otherwise identical 
chip. 
Display Codes 

What good is It if you can't read it, right? 
Fortunately there are a lot of ways to do 
that. For strictly numeric readout, there are 
llic old faithful Nixies, which use a 1-of-lO 
decoder, and seven-bar^ which takes a special 
chip. Seven-bar LEDs are making it big these 
days, and they can be driven directly from 
an IC, as can Numitrons (which I don't like^, 
as they lose segments too easily) and others. 
Many chips have provisions for leading- and 
trail ing-zero blanking, and some have latches 
built in for multiplexing, where one set of 
BCD (or hex) lines is connected to all 



decoders, and another input tells the in- 
dividual chip when the data is intended for 
it. Data is "frozen" in each chip and 
periodically updated, and all digits of the 
display are on continuously. Chips without 
latches can be multiplexed too, but only one 
is on at a time* Scanning is rapid and 
continuous, and all the digits appear to be lit 
simultaneously- With a large number of 
digits, since brightness is proportional to 
average current, and each digit is lit only a 
small portion of the time, peak current may 
be rather high. 

Another display system, variously called 
matrix, scoreboard, etc., has the characters 
formed by lighting a pattern of dots, and 
this is suited to just about any character, not 
just numerals. If only upper case letters are 
to be displayed, 5 x 7 is a popular choice, 
but with upper and lower case, legibility 
suffers and a denser matrix is used, 7 x 9, 9 x 
12, etc. This system can be used both with 

LED matrices and TV screens. Instead of a 
relatively simple decoder chip, a ROM is 
used, and called a character generator. 
Inputs for the TV version (usable with LED 
also) are the code for the character and the 
address (location within the matrix In binary 
code) of the dot which is to be on or off. 
There is only one output line; It is the on/off 
signal going direct to the CRT gun. Other 
circuits such as random-access memories 
(RAM) or shift registers, keep track of what 
characters are in what places and provide the 
proper ASCII (e.g.) code to the generator at 
the proper time. The column and row inputs 
to the ROM and the RAM are provided by 
counters which run from a master clock 
(oscillator). 

LED single line readouts are usually 
scanned a column at a time, and the cha- 
racter generator will have 7 outputs for a 5 x 
7 display. Inputs are just the code and the 
column. This allows for a seven-fold increase 
in brightness, as the dots in a column do not 
have to share the time among themselves. In 
the TV system, brightness is not a problem, 
and only one dot can be scanned at a time 
anyway. 

It is possible to get more well-defined 
characters in a TV system; 64 x 64 would 
only take six more bits (three for the 
column and three for the row) for the inputs 



AUGUST 1975 



117 



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to the ROM, and no more outputs. If you 
wish to display Chinese this would probably 
do it welL You would probabfy run out of 
room in the ROM^ but you can split it right 
down the middle and use two or four ROMs. 
Each split turns one input bit into a chip 
select function. 

There are other ways to generate cha- 
racters on a TV screen, such as making the 
beam follow the curvature of the letter. This 
is needed for such things as typesetting, but 
is unnecessarily complex for most appli- 
cations, and I will not go into it here. 

Other Aspects of Codes 

1 have purposely left out BCD to binary 
and back again, since this is a big enough 
subject for another separate article. Some 
basic arithmetic can be covered along with 
it I can't think of anything else to write 
about codes, but 1 think I'll take all these 
ideas and some others I have and whip up a 
complete amateur station completely run 
with a keyboard and a TV set. It may take a 
while, but there will certainly be a lot to 
write about when it*s done. 

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118 



73 MAGAZINE 



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If you have been trying to resurrect something from the pre-transistor past that more closely 
resembles the mechanism used to keep large ships in place, or if the sound of bumble bees 
is keeping you awake at night-REJOICEM! The ICOM 30A is here and working! 

Consider these reasons for owning an IC~30A: 
(1J Despite the fact that the radio ts completely solid state , it has output of ten watts 

(2) Receiver sensitivity is better than 0.6UV for 20 db of quieting 

and that means easy on the ears listening. 

(3) The IC-30A comes with five channels of the 22 channel capacity installed 

(4) Shielding is excellent because the unit is modularly constructed, 

(5) Your car tires will last long because the IC-30A weighs less than ten pounds. 

(6) Like its predecessors, the unit is equipped with a 9 pin plug in the side of the radio to 
provide you easy access to the discriminator and room for adding the necessary wiring 
for external accessories — with all this and more, for only $399.00. 



SEE ONE !! BUY ONE M AT YOUR ICOM DEALER TODAY 



Distributed by: 




ICOM 



ICOM WEST, INC. 
Suite 3 

13256 Northrup Way 
Bellevue WA 98005 



ICOM EAST, INC. 
Suite 307 

3331 Towerwood Drive 
Dallas TX 75234 



AlJf;uST 1975 



119 



DUPLEXER KITS 




PROVEN DESIGN 

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MOD. 62-1 6 CAVITY 135-165 MHz POWER 

250W ISOLATION GREATER THAN 
lOOdB 600 kHz. INSERTION LOSS .9 dB 
MIN. TEMP STABLE OVER WIDE RANGE 

PRICE $349. 00 

42-1 4 CAVITY SAME AS 6 CAVITY EX- 
CEPT ISOLATION GREATER THAN 80 dB 
600 kHz INSERTION LOSS .6 dB MAX 

PRICE $249. 00 

OTHER KITS SOON TO BE AVAILABLE 

146 to 148 MHz band pass filter. 1 296 & 2304 Intardlgital Mixers 
1 44 to 450 MHz 250w tube amp. 1 30 to 1 70 MHz notch filter kit 

NORTH SHORE RF TECHNOLOGY 




TUPTS 



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120 



73 MAGAZINE 




Hank Olson W6GXN 

P,0. Box 339 

Menlo Park CA 94025 



Build this Amazing 
Function Generator 



The increasing popularity of a relatively 
new piece of test equipment {the func- 
tion generator) has spurred at least two IC 
manufacturers to design special monolithic 
chips for this purpose. The Intersil 8038 and 
the Exar XR2206 are examples of such 
specially committed ICs, and several tech- 
nical articles using these ICs as function 
generators have appeared in the recent liter- 
atureJ*2 These nev^ ICs offer great sim- 
plicity in function generator construction, 
but offer the user very littfe "feel" for what 
is actually going on in the process of 
waveform generation. Since I find that the 

iMegirian, R., "Integrated Circuit Function Gener- 
ator", Ham Radio, Jan. 74, p. 22. 

2g re bene. A., "Generate Waveforms with a Single 
IC", Electronic Design, Sept. 13, 1974, p. 132. 



building of a piece of test gear is also a 
learning process, circuit flexibility and 
stage-by-stage analysis are important. For 
this reason, an older design for a function 
generator from a Motorola application note 
(ANSI OA) was the starting point. 3 

The Motorola application note AN510A 
by Bob Botos is actually the second edition 
of this publication, in which several printing 
errors in the earlier AN510 were corrected. 
So we can assume that the designs therein 
are at least five years old — pretty ancient in 
the fast-moving technology of the semicon- 
ductor era. However, Mr. Botos' design 
techniques are really timeless, and can be 

3 Botos, R., "A Low Cost, Solid State Function 

Generator", Motorola Application Note AN 510 A, 
1971, 



A I mi IQT 1Q7R 



121 



brought up to date by substitution of newer, 
better components as they become available. 
The original AN510A output amplifier 
section, for instance, is a real '*klooge'' by 
today's standards, and so it was replaced by 
a simpler ad-IC substitute. The original 
power supply used two dual-winding power 
transformers, four integrated bridge recti- 
fiers, and four power IC regulators. This 
rather elaborate supply was replaced with 
one inexpensive transformer, one integrated 
bridge rectifier, and two of the newer 
Raytheon ± regulator ICs, A feature in the 
new function generator is dc offset, a simple 
addition that is really worthwhile, 

The circuit of the function generator is 
shown in Fig. 1 ; note that four ICs as well as 
a number of discrete devices are used in the 
waveforming circuitry* In addition, two 
more power ICs are used in the power 
supply, shown in Fig. 2. A block diagram of 
the waveforming circuitry is shown in Fig. 3. 

The integrator is composed of U1 and 
Ql, an op amp and an emitter-follower to 
lower the op amp output impedance. 

The comparator is composed of U2, Q2, 

Q3, Q4, Q5, Q6, Q7, D8 and D9. U2 is an 
Emitter-Coupled Logic IC capable of 
extremely fast switching- Associated with, 
but not actually part of, the comparator are 
DIO, Dll and D12 which serve as voltage 



regulators to provide U2 with +1,4 volts and 
-3,9 volts. It is worth noting that Q4, Q5 and 
Q6 were originally designated as Motorola 
MPS-L08 types in AN510A, but since this 
transistor type is now obsolete, appropriate 
substitutions have been made* 

The 'Veference-switch" is made up of Dl, 
D2, D3 and D4. Note that D3 and D4 are 
dual diodes. Also note that RB in Fig, 3 is 
either R8 plus R1 or R9 plus R1 1 , depend- 
ing on the state of the reference switch. 

The *'sync-amplifier" is a simple 
differentiator, rectifier and emitter-follower. 
The square wave from the comparator is 
differentiated by CI 3 and R30. D7 allows 
only the positive-going spike to be passed to 
the base of Q8. This positive spike is then 
available at the emitter of Q8 for a sync 
pulse. 

The "sine wave shaper*' consists of D5, 

D6, Q9 and Q10. D5 and D6 act as '*soft" 

clippers on the triangle wave, and produce a 
near approximation to a sine wave. Q9 and 
Q10 simply act as emitter-followers after 
shaping — one NPN and one PNP, so that 
their emitter-base voltage drops cancel each 
other. 

Since it was necessary to attenuate the 
triangle wave {with the voltags divider 
R33-R34) to make it compatible with the 
shaping diodes D5 and D6, the resulting sine 



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Fig. 1, Function generator, waveform circuits. 



122 



73 MAGAZIIME 



nrvAC 



TRIAD 
F40)( 




BRI' MOTOROLA M 0*320 -3 
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Fig. 2. Regu/ated power supply for fijjiction 
gejierator. 

wave is smaller in amplitude than the 
triangular wave or square wave. To equalize 
the output levels of the three waveforms, 
simple "T" attenuators are placed in the 
triangle and square wave lines. These consist 
of R38, R39, R40 and R41, R42, R43 
respectively. 

Finally, the "output amplifier** consists 
of U3 and U4, a high slew-rate op amp and 
buffer amplifier. Note that the buffer is 
inside the closed loop of the amplifier. By 



adding in variable dc at the inverting input 
of U3 via a. 120k resistor, a "dc offset" 
adjustment is easily obtained. This "dc 
offset'* enables one to offset the three types 
of waveforms for testing of circuits which 
will accept only unipolar signals — such as 
logic circuits. 

The power supply utilizes a Triad F40X 
(26.8 Vet lA) transformer which combines 
low price, small relative size and high current 
capability. An integrated bridge and two 
Raytheon RC4194TK integrated circuits in 
the circuit of Fig* 2 provide ±1 5 volts and ±6 
volts for the waveforming circuitry. The 
RC4194TKs are heat-sink mounted to the 
chassis with T066 mica wafers for heat 
transfer and electrical insulation. The F40X 
transformer is mounted under the chassis to 
keep it electrostatically shielded from the 
top-mounted waveforming circuits. The two 
1000 uF filter capacitors are also mounted 
under the chassis because of the relatively 
large ac line ripple on them. 

The function generator is built into an 
old 7" X 8" X W steel equipment cabinet, 
to which an aluminum panel has been fitted. 
The aluminum panel was originally an old 
black-crackle finished relay rack panel which 
was stripped of paint and cut down to size- 
The left over portion of this same panel was 
made into the frequency dial, by rough 
sawing and turning down the outer diameter 
on a lathe. The large aluminum "spinner'* 
knob for the center of the frequency dial 
was also turned from a scrap of bar stock on 
the lathe. The basic planetary drive for this 




OUTPUT SELECTXJR 



OUTPUT 
AMPLIFIER 



SYNC 
OUTPUT 



■O 



AMPLITUDE CONTROL 



Fig, 3. Block diagram of function generator. 



AUGUST 1975 



123 



AY5-1013A UART S10.90. 2/S19.95 

8038 VCO S4.95 

MK5002 4 Decade counter $13.95 

9374 7 Segment Decode, Quad Latch. LED 

Driver $2.99 

MM5740AAEN ASCII Keyboard Encoder 

$17.99 

XR205 Function Generator $8.40 

XR210 FSK Demod $5.25 

XR320 Precision Timer $1.55 

XR2206CP Monolythic Function Gen$5.50 

XR2207CP VCO $3.85 

XR2240CP Programmable counter timer 

$4.85 

100V /3A Epoxy Diodes SPECIALIO/SI.OO 
600/jf/50V Etectrolytics SPECIAL10/S2.50 
MC1306P 1/2W Audio Amp $.70, 10/S6.00 

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rrsinimum order — $5 U.sy$15 foreign 
latest lists — 10^ stamp 



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control was a National Velvet Vernier 
salvaged from a surplus BC375 or BC191 
tuning unit. Those with fancier dial systems 
available or without access to a lathe and the 
above surplus drive units can use other 
methods — even a plain large knob. One will 
note that one of the tinning capacitors in the 
circuit of Fig. 1 is a 10 uF non-polar type. 
Because the author had the room in the 
cabinet, an old 10 uF 600 V transmitting 
capacitor was used. It was mounted on a 
homemade insulating mount, as otherwise 
stray capacity to the capacitor case was 
objectionable in this circuit. 

The relatively small amount of circuitry 
of the power supply is mounted under the 
chassis. The power supply should be the first 
section checked outj preferably before con- 
necting it to the waveforming circuits. Note 
that each RC4194TK has a 71.5k resistor 
from **case" to #3; this is the nominal value 
suggested by Raytheon. Sorting through 
one's 68k and 75k resistors will give a few 
values close to 71.5k — use these. The 37.5k 
and 15k resistors from pin =2 of the 
RC4194TKs will then be target values to 
give ±15 volts and ±6 volts respectively. 



Some juggling of these target resistance 
values may be required to give exactly the 
voltages desired. 

Assuming that the power supply has been 
checked out, as above, and puts out ±1 5 and 
±6 volts, the waveforming circuitry can be 
connected to it. The pots Rl, R8, R9 and 
R19 should all be set at mid range, and the 
pot R21 set at mint mum. The dc offset pot 
should also be set at mid range. 

With the scope on the wiper arm of R19, 
adjust this pot until the waveform looks like 
a square wave (i.e., the positive portion is as 
long as the negative portion). Then put the 
scope on the emiiter of Ql, and adjust R8 
and R9 until the triangular wave observed 
there has a ±2 volt value. R19 should be 
"re tweaked'* as above and then R8 and R9 
again. The scope can now be shifted to the 
output, and '*dc offset/' level, frequency 
and sine-shaping checked. 

This function generator has been a "silk 
purse from sow's ear" project for me, a 
useful piece of test equipment built up from 
odds and ends. While the semiconductor 
costs can be as high as $35.00, appropriate 

substitutions can trim this figure somewhat. 
To this end most of the diode (D) and 
transistor (Q) designations have several 
acceptable numbers given in the parts list 

Parts List 

D1, 2 — Silicon signal diodes: Motorola MSD6102, 

1IM4454,or1N914 

D3 — Dual Si. signal diode: Motorola IV1SD61 50^ or 

two 1IM4454, 1N914 

D4 — Dual Si. signal diode: Motorola MSD6100, or 

two 1N4454, tN914 

D&9 - Silicon signal diodes: Motorola MSD6102, 

lN4454,or 1N914 

Ql, Q8, Q9 - INJPM Xstr: Motorola 2N41 24 or 

HEP53, or 2N3643, or HEP-S0014 

Q2, Q3, Q7 - NPN Sw. Xstr: Motorola 2N709 or 

HEP50, or 2N3646, or HEP-S0J1 1 

Q4, Q5, Q6 - PNP Sw. Xstr: Motorola 2N4260 or 

HEP720, or2N3640, or HEP-S0019 

Q10 - PNP Xstr: Motorola 2N4126 or HEP57, or 

2N3644, or HEP^S0019 

Ul - Motorola MC1420G or MC1520G 

U2- Motorola MC1035P or MCI 235 L 

U3 - National Semiconductor LM318H, LM218H, 

or LM118H 

U4 — National Semiconductor LH0002CH or 

LH0002H 

D10 - Motorola 1 N4730A or HEP-Z0403 

D11, 12 - Motorola 1N4001 or HEP-R0O50 

■ 

. , . W6GXN 



124 



73 MAGAZINE 



THE FIRST AND STILL 
THE 

the exciting super 

compact IC230 



^^rrlOM ! fc:: 



ESQ: 



PUT OVER 67 CHANNELS IN THE PALMS OF YOUR HANDS 

SPECIAL FEATURES: 

No More Crystals . , . Over 67 ... fully synthesized channels available. 

All Channel Capability , . , Travel with confidence that you1l be able to work 
all repeaters along the way. 

Super Compact . . . 2.28" high x 6.14" wide x 9.72" deep at a weight of only 
5.5 lbs. 

• Quick Dismount Mobile Mount . . . Allows quick car installation. 

Easy Operation , . . Punch up frequency, select repeater or simplex mode, and 
you're on the air, (A crystal may be added for a unique repeater frequency,) 

Modular Construction ... In case of a problem, modules can easily be removed 
and sent for repair, A replacement module will be air mailed to minimize 
down time. 

Super Hot Receiver . . . Belter than .4uv / 20db, sensitivity, helical filters to 
eliminate intermod • . . plus a super E filter and a mosfet front end. 

IF THERE IS A SIGNAL, YOU'LL HEAR IT ON THE IC230! 

LA TCH ON TO THE lC-230 A T YOUR A UTHORIZED I COM DBA L ER 



Distributed by: 



ICOM 



— Dealerships Avatlabie — 



ICOM WEST, INC. 
Suite 3 

13256 Northrup Way 
Believue WA 98005 



rCOM EAST, rNC. 
Suite 307 

3331 Tower wood Drive 
Dallas TX 75234 



AUGUST 1975 



125 







For complete information package including 24 page cata 



QfPSj 



technical d#a, price list and sample 



AlUJr Users Group newspaper send $2.00 to: Altair Package, MITS, 6328 Linn NE, Albuquerque, 





NEWS 



Before the 
Federal Communications 

Commission 
Washington, D.C. 20554 

In the Matter of 

Amendment of Part 97 of 
the Commission's Rules 
to permit linking of 
amateur repeater stations 

Docket No. 20073 
RM2349 

Report and Order 
(Proceeding Terminated) 

Adopted: May 28, 1975 

Released: June 5, 1975 

By the Commission: Commissioners 

Hooks and Washburn absent, 

1. On June 5, 1974, the Com- 
mission adopted a Notice of Proposed 
Rule Making in the above-entitled 
matter which was published in the 
Federal Register on June 13, 1974 (39 
FR 20704), Proposals in this pro- 
ceeding contemplated amendment of 
Part 97 of the Commission's Rules to 
delete the proscription against inter- 
connecting more than two repeater 
stations in the Amateur Radio Service, 
i.e., the tandem operation of more 
than two repeaters. Comments as to 
these proposals were submitted by the 
parties listed in Appendix A. Each of 
these comments has been carefully 
considered as indicated in the 
following discussion. 

2. By way of background, in 1972, 
the Commission formalized specific 
rule provisions for the operation and 
technical development of amateur 
radio stations which can receive and 
automatically retransmit the signals of 

other amateur stations. {See the 
Report and Order in Docket No, 
18803, 37 FCC 2nd 225, 1972,) Prior 
to these rule changes, repeater stations 
had been authorized in the Amateur 
Radio Service under limited general 
rules that related primarily to any 
remotely controlled station. In that 



proceeding the Commission expressed 
the opinion that terrestrial repeater 
stations should be utilized only for 
i n t r a - c o m m u n i t y radio- 
communication. This and a desire to 
conserve spectrum led the Com- 
mission to adopt rules which would 
accommodate the majority of situ- 
ations. In March, 1974, the American 
Radio Relay League, Incorporated, 
submitted a Petition for Rule Making, 
RM-2349, to delete the portion of the 
rules which prohibits the inter- 
connection of more than two repeater 
stations* 

3. All comments supported the 
proposal as being timely and in 
genera! conformance with today's 
practical requirements for amateur re- 
peater operations. Some respondents, 
however, confused the proposal to 
permit unrestricted tandem operation 
of repeater stations with a proposal to 
eliminate the prohibition of crossband 
operation of such interconnected 
stations. The subject of crossband 
operation of amateur repeaters is 
being considered in a separate pro- 
ceeding, FCC Docket No. 20113. This 
proceeding deals only with the 
tandem operation of repeater stations 
which are being operated in the same 
frequency band. 

4, In line with our proposal, we are 
deleting the prohibition of tandem 
operation of more than two repeater 
stations. Certain requirements will, 
however, have to be observed by the 
licensees/trustees of all such stations 
which are interconnected. Since at 
least two different stations are in- 
volved in a system of interconnected 
repeaters, a system network diagram, 
showing all related stations in the 
system, must be submitted in accor- 
dance with Section 97.47(e) of the 
Commission's Rules by the licensee(s) 
of each participating station, This 
diagram should include any auxiliary 
link stations which may be used to 
effect the interconnection. It is re- 



quired even though the Inter- 
connection may occur only occa- 
sionally or on a part-time basis and is 
brought about by the Commission's 
need to be aware of which stations are 
involved in such a system, 

5. Licensees/trustees and control 
operators of att tandem operated re- 
peater and associated stations should 
remain aware that the interconnection 
of their station with any other station 
does not relieve them of the respon- 
sibility for proper operation of their 
station. If any of the participating 
stations are licensed to be operated by 
remote control, the submission of a 
revised system network diagram does 

not, in itself, alter the list of 
authorized control points for each 

remotely controlled station. Where 
the authorized control points of one 
station in a system of interconnected 
stations are also intended to serve as 
primary control points for other 
stations in the system, the station 
licenses of those other stations must 
be appropriately modified. 

6. The revised rules will afford 
amateurs considerably increased flexi- 
bility in the operation of repeater 
systems. Implementation of tandem 
operation of repeater stations will 
require no special applications. How- 
ever, as previously discussed, revised 
system network diagrams must be 
submitted to the Commision for each 
participating station. These diagrams 
should be sent directly to the Federal 
Communications Commission, Gettys- 
burg, Pa., 17325, and should be 
clearly marked as to the name(s) of 
the licensee(s) and the callsignsof the 
participating stations. 

7. In consideration of the foreg- 
oing, the Commission finds that 
amendment of the rules to permit 
unrestricted interconnection of 
amateur repeater stations is in 
public interest, convenience, 
necessity. 

8. Accordingly, pursuant 
authority contained in sections 4(i) 
and 303(r) of the Communications 
Act of 1934, as amended, IT IS 
ORDERED That, effective July 11, 
1975, Part 97 of the Commission's 
Rules IS AMENDED as set forth 
below: 

§97.89 [Amended] 

In §97.89, paragraph (c) is deleted 
and designated ''[Reserved] ". 

9. IT IS FURTHER ORDERED 
That this proceeding IS TER- 
MINATED. 

Federal Communications Commission 

Vincent J* Mullins 
Secretary 



the 
and 

to 



AUGUST 1975 



127 




CONTESTS 



Editor: 

Robert Baker WA1SCX 
34 White Pine Drive 
Littleton MA 01460 




CALGARY CENTENNIAL 

CALGARY-to-MOBILE CONTEST 

Starts; 1700 GMT July 26 

Ends: 1700 GIVIT August 7 

The contest is to promote hospitality 

and interest in the Calgary Centennial 

Convention, All contacts nnust be 

between CY stations (fixed or mobile) 
and convention guests who are not 
Calgary residents and who are oper- 
ating mobile on their way to the 
convention, 
EXCHANGE: 

Report; name, location of mobile. 
One contact per band per mode per 
day. 

SCORING: 

Score 1 point between CY and mobile 
who is within city limits of Calgary, 2 
points between CY and mobile out- 
side city but within Alberta, 3 points 
between CY and Sask, B,C*, or Mont, 
4 points between CY and any other 
QTH. 

FREQUENCIES: 

Mobiles look for CY stations after- 
noons and evenings ± 20 kHz of 3770. 
When in range, check 34-94, 28-88, 
and 146,46-147.00, 
LOGS: 

Logs must be deposited at the Calgary 
Centennial Convention registration 
desk no later than 2359 GMT August 
2. Show date and time in GMT, mode, 
band, reports, first names, and loca- 
tion of mobile. 

ILLINOIS QSO PARTY 
Starts: 1800 GMT Saturday, August 2 

Ends: 2300 GMT Sunday, August 3 
Rest period from 0500 to 1200 GMT 
Sunday, August 3. The 13th Annual 
Illinois QSO Party is sponsored by the 
Radio Amateur Megacycle Society, 
Inc. (RAMS). Same station may be 
worked with each mode (CW and 
phone) on each band. No repeater 
contacts allowed. Contacts with 
K9CJU/9 aboard U,S,S. Silversides 

submarine will count as 5 regular 
contacts for scoring. The word SUB- 
MARINE will be added to the ex- 
change sent by K9CJU/9. Send an 
SASE for special QSLs that will be 
available. 
EXCHANGE: 
Illinois stations give RS(T) and 



county. Others, give RS(T) and state, 
province, or country. 
SCORING: 

Illinois stations add the number of 
Illinois counties, states, Canadian pro- 
vinces, and ARRL countries. Multiply 
tota! by the number of QSOs for 
score, Illinois mobiles, add 200 points 
to score for each county operated 
from (except home county) with 10 
or more contacts made. Other sta- 
tions, multiply total number of con- 
tacts by county multiplier. For Non- 
IL only, each group of eight contacts 
with the same county gives one bonus 
multiplier. Sum of counties worked 
plus bonus multipliers equals county 
multiplier, 
FREQUENCIES: 

60 kHz from tow end of CW bands. 25 
kHz from high end of phone bands, 
and 21375 & 28675. 25 kHz from low 
end of Novice bands on the half hour. 
AWARDS: 

For Illinois stations, certificates to top 
three scorers in Si ogle-op. Multi-op, 
Portable {non-home county). Mobile, 
and Novice categories. Others, awards 
go to scorers in Fixed, Mobile or 
Novice groups in each state, Canadian 
province or county from which 2 
entries are received. Top scorer in any 
club mentioned in 3 entries also rates 
an award. Decisions of contest com- 
mittee are final. 
LOGS: 

Legible logs must be submitted. A 
separate summary sheet must show 
name, address, call and category of 
operation. Summary should also show 
number of contacts, list of multipliers, 
and claimed score. Entries should be 
postmarked no later than Sept. 15, 
1975. Include a business size SASE 
and mail to: RAMS - K9CJU, 3620 
N. Oleander Avenue, Chicago IL 
60634. 

NEW JERSEY QSO PARTY 
Two Periods (GMT) 
2000 Saturday, August 16 to 0700 
Sunday, August 17 

1300 Sunday, August 17 to 0200 
Monday, August 18 
The 16th Annual NJ. QSO Party is 
sponsored by The Englewood Ama- 
teur Radio Assoc, Inc. Phone and CW 



are considered the same contest. A 
station may be contacted once on 
each band; phone and CW are con- 
sidered separate bands. NJ. stations 
are requested to identify themselves 
by signing "DE NJ" or "NJ CALL- 
ING" and NJ. stations may ,work 
other N J. stations. 
EXCHANGE: 

QSO Nr., RST and QTH - County for 
NJ,, ARRL Section or country for 
others, 
SCORING: 

NJ. Stations - W, K, VE, VO QSOs 
count 1 point while DX QSOs count 3 
points. Final score is sum of QSO 
points times number of ARRL Sec- 
tions (including NNJ & SNJ), KP4, 
KH6, KL7, KZ5, etc., count as both 3 
point DX QSOs and as section multi- 
pliers. Others - Multiply number of 
completed NJ. QSOs by number of 
N.J. counties worked (maximum of 
21), 

FREQUENCIES: 

1810, 3535, 3735. 3905, 7035, 7135, 
7235, 14035, 14280, 21100, 21355, 
28100, 28600, 50^50.5, 144-146. 
Suggest phone activity on even hours, 
15 meters on odd hours between 1500 

& 21 00 GMT, and 160 meters at 0500 
GMT. 

AWARDS: 

Certificates will be awarded to first 
place stations in each NJ. county, 
ARRL Section, and country. Second 
place certificates will be awarded 
when 4 or more logs are received. 
Novice and Technician certificates will 
also be awarded. 
LOGS: 

Logs must show GMT date and time, 
band and emission in addition to the 
required exchange information. First 
contact for each claimed multiplier 
must be indicated and numbered, A 
check list of QSOs and multipliers 
should be included. Multi-operator 
stations should be noted and calls of 
all active operators listed. Logs and 
comments should be received not later 
than Sept. 13, 1975 and should be 
sent to: Englewood Amateur Radio 
Assoc, Inc, 303 Tenafly Road, Engle- 
wood, NJ 07631. Include a size #10 
SASE for results. 

ALL ASIAN DX CONTEST - CW 

Starts: 1000 GMT Saturday, 

August 23 

Ends: 1600 GMT Sunday, August 24 

Non- Asian stations work Asian 
stations, KA contacts do not count. 
CLASSES: 

Single operator, single and all band, 
ulti-operator, single transmitter, all 



128 



73 MAGAZINE 



band only. Club stations are con- 
sidered Multi-operator stations. 
EXCHANGE: 

RST plus age of operator, YLs send 
"00" for age. Each operator of Multi- 
operator stations will give his age 
while operating, 
SCORING: 

One point per QSO. Asians, use nunrv 
ber of non Asian countries worked 3S 
multiplier. Non- Asian stations, use 
number of prefixes of Asian stations 
worked as multiplier. 
FINAL SCORE: 

The total QSO points from each band 
times the sum of the multiplier on 
each band equals the final score, 
AWARDS: 

Certificates awarded to top single 
operator, all band and each single 
band, in each country and USA call 
area; up to the fifth rank where 
returns justify. In addition to the 
certificates, medals will be awarded to 
the continental all band leaders and 
multi-operator continental leaders. 
LOGS: 

Use a separate log for each band, show 
all times in GMT, fill in country or 
prefix column first time worked. A 
summary sheet is required, showfng 
scoring and other information. 
Include a signed declaration that all 
rules and regulations have been 
observed. Logs must be received no 
later than Nov 30, 1975. Logs should 
be sent tor J,A.R,L Contest Con> 
mitee, P.O. Box 377, Tokyo Central, 
JAPAN. Include an IRC and SAE for 
results. 

FOUR LAND QSO PARTY 
Starts: 1800 GMT Saturday, 

September 6 

Ends: 0200 GMT Monday, 

September 8 

The Sixth Annual Four Land QSO 
Party is sponsored by the Fourth Call 
District Amateur Radio A^ociation of 
the LA.R.S. The lame station may be 
worked again on each band and/or 
mode fixed, and repeated again if 
operated portable or mobile, and from 
each different county, 
EXCHANGE: 

RS(T), county and state for 4th call 
district; state, province or country for 
others. 

SCORiNG: 

Fourth call district stations score 1 

point for W/VE QSOs, 3 points for 

DX contacts (include KH6 and KL7); 
final score is total points times states 

and provinces (states and provinces 
counted only once). All others score 2 
points per QSO and multiply by the 
number of fourth district states and 



counties. Count each state and county 

only once, 

FREQUENCIES: 

CW: 3575, 7060, 14070, 21090, 

28090 plus or minus 10 kHz. Phone: 

3940, 7260, 14340, 21360, 28600. 

Novices: 3710, 7110, 21110, 28110 

plus or minus 10 kHz. 

AWARDS: 

Certificates to top scorers in each 

state, VE province, and country. 

Second and third place awards when 

scores warrant. HHTA (High Honor 

Trophy Award) certificate to high 
scorer in four-land, high W/K, out of 
four-land, VE and DX country. Also, 
county awards to fourth call district 
states and special awards to Novices, 
SWLers, and B/H (blind/handi- 
capped). 
LOGS: 

Contestants must mail logs with scone 
within thirty (30) days of the end of 
party to 4th District A,R,A., Att: Bob 
Knapp W40MW, 105 Dupont Circle, 
Greenville NC 27834. Include an 
SASE for contest results, 

WASHINGTON STATE QSO PARTY 
Starts: 2000 GMT Saturday, 

September 13 
Ends: 0200 GMT Monday, 

September 15 

The Tenth annual Washington State 
QSO Party is sponsored by the Boeing 
Employees' Amateur Radio Society 
(BEARS), and all amateurs are invited 
to participate. All bands and modes 
may be used. Stations may be worked 
once each band and each mode for 
contact points and more than once 
each band/mode if they are additional 
multipliers. 
EXCHANGE: 

Washington stations send QSO num- 
ber, RS{T), and county. All others 
send QSO number, RS(T), and state, 
province or country. 
FREQUENCIES: 

CW: 3560, 7060, 14060, 21060, 
28160. Phone: 3835, 7260, 14280, 
21350, 28660. Novice: 3735, 7125, 
21150,28160. 



SCORING: 

Washington stations score one point 

for each contact (including contacts 

with other Washington stations). All 
others score two points for each con- 
tact with a Washington station. Wash- 
ington stations multiply total contact 
points by the total of different states, 
Canadian provinces and other foreign 
countries worked. All others multiply 
total contact points by the total of 
different Washington counties wortced 
(39 maximum). There will be an extra 
multiplier of one for each group of 
eight contacts with the same Washing- 
ton county. 
AWARDS: 

Certificates will be awarded to the 
highest scoring stations (both single 
and multi-operator) in ^ch state, 
Canadian province, foreign country 
and Washington county. Additional 
certificates may be issued at the direc- 
tion of the Contest Committee. 
Worked Five BEARS Awards are also 
available to anyone working five club 
members before, during or after the 
QSO Party (unless previously issued). 
All QSO Party entries will be screened 
by the Contest Committee for 
possible Worked Five BEARS Awards. 
Worked Three BEAR Cubs Award is 
available for working three Movice 
members. 
LOGS: 

Logs must show dates and times in 
GWIT, stations worked, exchanges sent 
and received, bands and modes used 
and scores claimed- Include check 
sheet for entries with more than 100 
QSOs, Each entry must include a 
signed statement that the decision of 
the Contest Committee will be 
accepted as final. No logs can be 
returned. Results of the QSO Party 
will be mailed to all entrants. SASE is 
NOT required! Log sheets and scores 
must be postmarked no later than 
October 13, 1975 and sent to: Boeing 
Employees' Amateur Radio Society, 
c/o Contest Committee, Willis D. 
Propst K7RSB, 18415 38th Avenue 
S., Seattle W A 98188, 




CONTEST CALENDAR 



|uly 26 - Aug 7 
Aug 2-3 
Aug 2 ' 3 
Aug 2 - 3 
Aug 9- 10 
Aug 16- IS 
Aug 23 ' 24 

Sep t 6 ' S 
Sepi 13-14 
Scpi 13-15 
Sepi 27 ' 29 



Calgary CenlcnniaJj Calgary- to- Mo bile 

WAE DX Contc*.! ■ CW 

yOODnlesi 

llfinoivOSOPjuv 

European DX Cojiiesi - CW 

New Jcrttfy QSO Party 

All Asijji Content - CW 

ARRL VHF QSO Parly 

Four Land QSO Party 

ELfropean DX Contest - Phone 

Wa5hinglon Slalc QSO Party 

Del Li QSO Parly 




AUGUST 1975 



129 



ou goons d;;n * ' 




BEST 



I Insist th^^t you ^r ' 
from page (( 

After you experiment with a 
Flipper and tape system, you may 
want to try some of those ''multi- 
screen" effects that you see in movies. 
You can add more Flippers and pairs 
of projectors (if you don't feel like 
buying them, some college com- 
munications departments are buying 
whole systems), but you run into the 
probtem of how to put that many 
tones on tape, Touchtone signalling; 
]ike you do for autopatch, might 
work* However, a commercial 
synchronizer that costs (gasp) $1200 
uses a different system. It develops a 
pulse train very rapidly^ and frequen- 
cy-shifts an audio tone to put the 
commands on tape. The big improve- 
ment over touch-tone is the fact that 

this system controls nine channels, 
and can operate them afl simultan- 
eously. 

If any of you gents or ladies have 
had experience building anything 
complicated like that^ would you 
write me? If nothing else, this might 
develop an interesting method of re- 
peater control. 

I want to thank you for three 
months of interesting reading. I have 
no ham license, but I do have a 
commercial First Phone, and I am 
fascinated by the great variety of 
articles you print. The series exposing 
Ma Bel! is manna from heaven, and 
your other articles are more candid 
than anything I have read since before 
I was bom< (I was an early learner J 

A relative of mine is a rabid CBer, 
and has stuck one of those curbed 
linears on his set. I have been trying to 
talk him into becoming a ham, but he 
claims that Morse code and electronics 
are too hard, and besides, he says all 
hams are conceited cottonpickers. Can 
you tell me what a cottonpicker is? I 
hear this word from CBers, on and off 
the air, and it appears to have a mystic 
significance, like "Om mane padme 
cm" and "Hare Krishna". Can any- 
body translate, please? 

Thomas E. Reed 

Chief Engineer, KBIL Radio 

Saint Louis University 

1220 Midland Blvd. 

University City MO 63130 

The Michigan Radio Doctor and 
friend supply one cotton pickin" 
definition on page 93. — Ed. 



I just received my June issue of 73 
and after going over it cover to cover 
and back again, I have one comment 
to make: It's the best damn ham mag 
I've ever read! I've subscribed to the 
other mags (CQ and QST) and I must 
admit that they are not even a close 
2nd to 7a 

I think I got the best enjoyment 
out of your editorials and letters from 
your readers. 1 would like to see more 
articles for the Novice and beginning 
ham like QST once had a long time 
ago. 

Not being an engineer, fust a ham 
that likes QRP and home brewing all 
of my gear, I like to see articles that 
the ordinary ham who doesn't have an 
EE or a complete machine shop at his 
disposal can duplicate, I run anywhere 

from 500 mW to 35 Watts in power 
on all of the Novice bands, and have 
much enjoyment in talking to these 
hams because they usually don't have 
the hello-goodbye QSO that is mostly 
the rule on the bands today. 

Keep up the good work, Wayne, 
and you can bet that when my one 
year subscription to 73 is up, I'fl 
renew for many years. 

Tom Cullen Jr, K1WXK/W1NXZ 

2 Westview Dr 
Wallingford CT 06492 

STOP THfS CHE A TING 

I read ur "In Pursuit of the Perfect 
SSTV Picture" on p, 73 of May 75 
"73 Magazine" with great interest, I 
started SSTV in Dec. 1972 with a gift 
cassette recorder "Standard SRT1 1 5" 
which my daughter had bought me as 
a present at KV4AA's shop on St. 
Thomas V,L when she was a nurse on 
the next Island of St John — she has 
recently moved to Hugo, OkL I soon 
found that the absence of a "turns 
counter" made finding a spot again on 
a cassette in a hurry an impossibility. 
Therefore In Jan. 1973 I bought the 
SONY TC 129 stereo deck, the later 
model of the one recommended by 
ROBOT, and it is excellent. 

When you review the lengths of 
ca^ettes u do not start on a real short 
length; I use 3 and 6 minute Endless 
Cassettes, the EC-3 & EC-6 (there is 
also a one minute one) made by TDK 
Electronics Co. Ltd of/in Japan^ and 
find them excellent for pre-recorded 
information e.g. 3m for 2xCQs, 6 min, 
for Name, QTH, station equipment. 



etc,, etc, another 3 minute for ORZ 
de G3WW, ok from G3WW, hw copy? 
pse K., etc,, etc, 

Ur SSTV column and articles are of 
great interest to the SSTV gang in 
Great Britain & are regularly discussed 
each Sunday morning about 0730 gmt 
on the 80m SSTV Net on 3735 kHz; 
"SSTV Video Analysis" by WB8DQT 
in Jan_ 75 issue has been applied to 
two home built monitors (SSTV) with 
the results forecast, while it saved me 
(?) $99.0 in nt having to buy the 
ROBOT mod, kit to up-date my 70 
Monitor, already modded to 70A, to 
70B. I already have the Fast Scan 
Montr Model 61, so by adding his 
(WB8DQT's) Video analyzer with 
single sided discriminator to my 
Robot Monitor I achieved a better- 
than-70B result as with the 61 I eld 
set up camei^ 80A on the F/S Mon 
while receiving SSTV on the 70A- 

BUT IT IS NECESSARY TO FULLY 
FLOAT THE EXTRA SINGLE- 
SIDED DISCRIMINATOR WITH A 
three pole (nt double pole) double 
throw switch when nt in use, as if the 
input is left connected to the Robot 
Li miter Output the circuit will "ring'* 
and distort the video — try it and see. 

G3GGJ has made up for me both 
the W0LMD Keybrd (CQ-Sept 74) 
with PC Board by W80ZA, to give me 
the very first one in Europe in ApL 
75, and the SSB/SSTV Bandpass filter 
by DJ6HP (CQ-DLAug. 1974); there 
are now two SEEC Keyboards in HB9 
land and one in 0D5> 

I used ur Navassa battery tape 
recording method for /M SSTV recep- 
tion (see last Fall's ROBOT News- 
letter) but with an outboard tuning 
indicator between FT J 01 & recorder; 
did u know that if an SSTV signal is 
recorded "off tune" it can be restored 
to full intelligibility by transmitting 
the tape thru a dummy load & receiv- 
ing that transmission on a sep. rx 
which in turn can be tuned to give an 
intelligible "picture" of what is on the 
tape?? Finally, this year's Worldwide 
SSTV was AGAIN a FARCE; the rules 
should be the SAME FOR EVERY^ 
ONE; nt the Ws praying in aide the 
FCC reqmnt for voice station identifi- 
cation at start & end of each qso while 
the rest of the world most nt utter a 
word, and then expanding this to 
"This is WB4.., calling CQ SSTV 
contest" - "Hallo, W2 . . ,, did u get 
ur report ok?" "Yes WB4 I got my 

m 

report ok at 5.7 but did you give me 
010 or 020 in video?" "No, I gave u 
020 & thanks for my 5.9" - ALL 
THIS SORT OF EXCHANGE BY 

Continued on page f32 



130 



73 MAGAZINE 







1/-" 





3" X 4" X 1 'h 

EXTEND YOUR COUNTER to 500 MHz!!! 
Can be used with Any counter capable of 5 
MHz. 

FmaX greater than 500 MHz. 

HIGH INPUT SENSITIVITY: less than 150 
mV needed at 500 MHz — overload protected 

HIGH INPUT IMPEDANCE: 500 Ohms 

OUTPUTS: ^10 and -100 TTL compatable 

INCLUDES POWER SUPPLY 

PS-Kkit $ 89.00 

PSA wired and tested $109.00 

BRAND NEW! P'"^ ^-^^ postage 

500 MHz COUNTER Calif, residents add 6% sales tax 

WRITE FOR DETAILS 








P.O. Box 961 S 

Temple City, Calif. 91780 



AUGUST 1975 



131 




I in;%l3t t 



from page 130 



yoa prl:;: tv 



VOICE. Let evryone use voice for 
station identification worldwide AND 
FOR NO OTHER PURPOSE and stop 
this cheating, is it not now marvelous 
to think how ur review of Voice 
Operated Switch (for a Mobile trans^ 
mitter) in CQ. August 1958 (when \ 
telephoned u about it in NY from 
Princeton NJ) has become the world- 
wfde VOX system? 

Richard Thuriow GSWW 

2 Church Str. 

Wimblington, March 

Cambs. England 

STAY THE SAME 

I'm enclosing a credit memo you 
'issued to me, apparently when I paid 
for a subscription tv^ice. Please apply 
the amount toward extending the 
subscription, advising me of the date 
the extended subscription will run 
out (Them aren't many magazines 
that I would consider subscribing to 
for such a length of time. Stay the 
same J 

Don Sawyer 
Roswell NM 



VOICE niwrii [r utfr 

I would like to order several of 
your cassette tapes for learning the 
code and theory for friends of mine. 
However, before sending the Basic 
Code and 6 wpm tape, I would like to 
know if the letter characters are sent 
at a speed of approximately 14 to 15 
words per minute with spacing 
between the characters to make the 
speed only 6 words per minute. I 
understand this is the new method (as 
I was taught that way), wherein you 
do not have time to count the dits and 
dahs yet you learn the characters at a 
fast sending speed so that when you 
increase your speed you merely close 
the gap between letters, etc. Also this 
does away wrth hearing slowly sent 
characters and when you increase the 
speed the dahs won't sound like dits. 

I'm sure you know what I mean 
since you are in this business. I've 
heard various tapes and records by 
AM ECO and Radio Shack and they 
are terrible. A friend of mine bought a 
Radio Shack tape for code it is so 



noisy and bad (and the characters are 
also sent at slow speed) that when you 
hear these same characters sent at a 
high speed it doesn't sound the same. 
Please do not send these two tapes if 
they are not what I want. This is also 
why I have not sent money with this 
order, as I don't know if it is what I 
want for my friend. Otherwise I will 
make up my own tapes for him, but 
Vd rather save time and let him buy 
yours, if they are what he should 
have* 

Afso, on the basic tape, do you give 
the character in voice as you first 
learn the character or is it written on a 
sheet of paper? I think voice with tlie 
character as in a class is best. 

Thank you kindly. 

Mervrn Behlen WA6SMG 

Fresno CA 

Yes, f have my voice on the basic tape 
te/fing about each character. And the 
letters are all sent at 13 wpm with 
spacing for 6 wpm so you only have 
to learn the code one time . , . by the 
sound This is by far the fastest 
system of teaming the code and, as far 
as I know, only my tapes use this 
fantastic system — Wayne. 

m 1 VAC 

Having recently subscribed to Hot- 
line, 1 am very pleased with it. This is 
really worth the price- If the price was 
twice as much it still would be a 
bargain) 

Re your editorials: 1 agree that the 
new FCC proposals would definitely 
hurt amateur radio, I think the code 
test should be lowered to 5 wpm and 
left there for all classes. And t also 
agree that only two classes of licenses 
should be issued. 

But as uaial, the FCC will probably 
ram the new rules down our throats to 
the detriment of amateur radio. If this 
happens our numbers will decrease, 
not increase! 

Which gets me down to the point 
that now interests me, because \ sell 
CB and some ham equipment in a 
store which I recently put in business. 
When I first opened I thought that 
there would be some interest in ama^ 
teur radio but so far t liave ex- 
perienced very little. Most CBers don't 
care a bit about getting their tickets. 
This to me is tragic. CB now is a 
bunch of lawbreakers who don't use 
call letters, swear on the air, run over 
power, give location of police cars to 
break the taw. throw carriers^ and just 
are plain ignorant! Wfien I was on CR 
irr the Rarly and j 1960*s, ca 



tetters were used and people operated 
properly most of the time. To buy a 
CB rig and try to use it is an exercise 
in futility, as you will ^t blown off 
the air by people who just don't care. 
Too many people are on the few 
channels that there are. 

A complaint I hear quite often and 
have noticed myself a bit is the lack of 
interest many amateurs take in getting 
new people interested in our hobby. 
There are too many people who don't 
want new members in our ranks. This 
is why some good people have gone 
bad with CB radio. 

I sure hope things change for the 
better, because they have been getting 
worse since the ARRL incentive plan 
ten years ago, 

I am really glad you understand the 
issues — the other magazines sure 
don't. I let my subscription to CQ 
lapse. It has gotten very poor, wrth 
few pages* 

Well, I'd better go now. Thanks for 
taking the time to read my letter- 
Keep up the really good work, and 
fight for what you believe in. 

Pete K. Hons 
Portage PA 

nsaovs coder v 

You may enter my name and call 
on your list of satisfied code tape 
users who, after mastering that mean, 
vicious piece of "Morse codery" put 
out by 73 Magazme under the guise of 
14 wpnrv passed his 13 wpm code test 
with ease, I might add that I failed it 5 
times prior to using your tape for 
practice, I think anyone who wants to 
spend the time mastering this ex* 
tremely tough tape should have no 
problem passing the test before an 
FCC examiner — even with the jitters 
that accompany the test. By the way, 
1 now have my Advanced Class test 
passed and am waiting for my ticket, 

Jim France WASH HO 
Massillon OH 



ASTOMSIfhUClAm 

Acting on the advice of some smart 
ham, 1 ordered your Advanced Study 
Guide (after about nine months of 
straggfe with several other books). 
Two months later I passed it (much to 
the astonishment of the rest of my 
hiim clubl). Many thanks. 

Phrl Litchfield WA10FP 
rJew Canaan CT 

Oyftiffued on page 136 



132 



73 MAGAZINE 



Autobiography 



•) 



Ancient Aviator 



W. &nger Green 
1379 £ 15 Street 
Brooklyn NY 11230 






The Kelly Field flight training was 
very interesting. We didn't just fty 
around aimiessly. Each day some 
aspect of our ground training was put 
to use in the air. 

Visual reconnaissance missions (There 
were several of these to different 
towns): We were instructed to fly over 
a certain town or district, usually 
within a 50 mile radius, and make a 
sketch of the area indicating any 
features of military interest such as 
factories, railroads, highways, water 
towers, flying fields, etc, 
Aeria/ Photography (Several to various 
locationsj: Same pfbbedure as Visual 
Recon Missions except that we photo- 
graphed strategic places. I even took a 
good shot of Art Caperton riding on 
the turtle back of another ship. 
Puff target range: We dropped simu- 
lated bombs on the smoke bomb 
range and were marked according to 
our accuracy. 

Artillery Reguiage: This was more fun. 
It was done in cooperation with a 
Field Artillery unit at Camp Stanley 
(about 30 miles away). Our job was to 
fly over a target at a fow altitude and 
direct the artillery fire {live ammo) to 
right, teft, forward or backward of the 
target center. The radio equipment we 
had for communication with the artil- 
lery consisted of a transmitter with 
key and an antenna that traifed betow 
the plane with a fish (weight) to hold 
it down and a reel in the rear cockpit 
to raise and lov\^r it. One time I tried 
to climb too fast with the antenna out 

and the DH fell off into a turn of a 
spin. This wound the antenna around 

the tail of the ship. The rudder didn't 

work too well but the elevators were 

OK, so I got back to the field and 

landed with no trouble. I didn't get a 



Everyone enjoyt^d a wiJd orgj of 
flyinp calndated \o rfraw flowerH, 

very good mark on that mission. 
Aerial Gunnery: For this work we 
spent several days at Ellington Field 
(near Galveston). Small ponds, 
shadows, panels and birds were our 
targets. Live ammunition was used in 
the two Lewis machine guns which 
were mounted on a scarf mount over 
the rear cockpit While we were at 
Ellington the rigid flying rules of 
Kelly Field were dispensed with. 
Everyone enjoyed a wild orgy of 
flying calculated to draw flowers. 
However, all eventually returned to 
Kelly more or less safely. Although 
the return weather was CAVU (clear 
and visibility unlimited} some got lost 
on the way and didn't straggle in to 
Kelly until the next day. 
Cro^ Country Trips: The trip to 
Ellington and return was our first, 
about 235 miles each' way. Our 
longest trip was to Post Field, Okla- 
homa, via Dallas, with return via 
Waco. An overnighter of about 720 
miles if you flew in a straight fine. 
There were several other shorter cro^ 
countries of up to 300 miles. 
Formation Flying: Only about ten 
hours of this flying was done by our 
observation group. Five ships to a Vee 
formation, A lot of this practice was 
in formation take off s, lands and 
turns. The object was to keep sway 
from the other fellow and not let him 
put his wrng in your lap. 

As we approached Love Field, 
Dallas, on our way to Post Field, I was 
driving the ship. As I came in to land I 
saw giraffes, zebras, camels, elephants 
and other animals grazing on the field. 



I decided to circle the field again 
while I reviewed what I had eaten in 
the last 24 hours and asked Munson in 
the rear cockpit if what I was seeing 
was really there. Affirmative, Then I 
managed to land without hitting any 
of the beasts. When I climbed out of 
the ship an over-friendly black bear 
came up to be petted. This one 
exuded that rare combination of B,0, 
and halitosis. I have a snapshot of this 
delightful experience. 

When Munson and I were coming in 
to land at Kelly from our cross- 
country trip to Post Field, we had a 
slight mishap that could easily have 
been much worse. It was almost dark 
and what we didn't know was that, 
during the two days we were away, 
they had put up some goal posts for a 
football field, one of which was right 
on the hangar line. Munson was pilot- 
ing and made his landing approach in 
the usual manner. He landed and 
taxied up to our hangar. Then we 
found out that on our approach we 
had hit one of the goal posts with our 
wing and broken the post off. The 
fortunate part of the mishap was that 
contact with the goal post was at the 
root of the right wing (next to the 
fuselage). If it had been farther out on 
the wing we would most probably 
have been in serious trouble. 

This masterpiece of engineerings built 
with a heavy Armv hand, looked 
pretly ferocious sitting on the ground 
— but onJy Jimmy Doolittle managed 
to get it around the field, 

I can't leave Kelly Field without 
telling you about the G.A.X. (ground 
attack experimental}. This was a 
masterpiece of aeronautical engineer- 
ing with a heavy Army hand laid on* I 
understand that only two of them 
were ever built, and if they had tried 
to fly #1 first they would have quit 
work on #2, The one I refer to was 
housed in a [arge hangar on the far 
side of the field. It was a large biplane 
powered by four liberty engines, 
gunner's cockpits forward and aft and 
half inch armor all around the two 
pilot cockpit. It looked pretty fero- 
cious sitting on the ground but the 
main trouble with it was that it had a 
ceiling of about 200 to 300 feet on a 
cool day. The only time I saw it fly 
was when we put on an aerial revue 
for General Patrick, Chief of the Air 
Service, Jimmy Doolittle managed to 
get it around the field twice at full 
throttle with very, very shallow turns. 

Next month I'll tell you about my 
return to civilian life and of some of 
my first "gypsy" flying experiences. 



AUGUST 1975 



133 




BUI Pasternak WA6iTF 
14725 Titus St =4 
Panorama City CA 9 J 402 



PANORAMA POLLTANAT 

''PACIFIC TELEPHONE FILES 
SUIT AGAINST 73 MAGAZINE" 
. . • and now that vwe have your atten- 
tfon ViB shall move on to other 
matters. Not that I don't have my 
own opinions on this historic event — 
I just do not feel that Looking West is 
the proper place to express them. 
There is just too much other news to 
report and events to cover to justify 
steering this column in that direction. 
Therefore, Looking West will still be 
the same old column you have come 
to know these past few years and 
thanks to this magazine's editorial 
policy, I will be able to cover the 
aforementioned legal action elsewhere 
in print, I assure you that I will be far 
from silent on this issue, since it 
affects the future of each of us — both 
as individuals and collectively. 

I have a rather strange policy in 
writing this column, I have no interest 
whatever in printing items that tend 
to bring down amateur radio or, 
through innuendo and gossip, to in 
any way bring harm to any individual 
or group within the amateur com- 
munity. It IS my feeling that there are 
enough individuals devoted to doing 
just the opposite, and someone has to 
point out the good and dwmll upon it 
Apparently most of you seem to agree 
with this policy. As a direct result of 
It, v\« have been able to bring you the 
type of news items that you seem to 
enjoy. On the other hand, some have 
accused me of being a "Polfyanna" — 
wh-^t they ^y is dig deep and give us 

the dirt* To those I say please look 

elsewhere since I have no intention of 
changing my policy; you will find the 
good news here and the "dirt" will 
have to come from someone else. 

With the aforementioned in mind, I 
am happy to report that it looks as if 
the California Amateur Relay Coyncil, 
a state-'wide VHF/UHF frequency co- 



ordinating body, has survived its 
internal political unrest and wifl re-or- 
ganize its structure along the lines of 
the report submitted by the "Blue 
Ribbon Panel" organized for that 
specific putpose. In its final report 
given June 7 at Santa Barbara, it was 
recommended that regional 
management be adopted with given 
individuals or groups being appointed 
to oversee the needs of these areas in 
relation to spectrum management as 
well as other forms of peripheral 
support to all special interest groups 
involved in FM communications. 
There would be Northern, Southern 
144/220 and Southern 50/450 and up 
coordinators assigned initially with 
invitation left open for other interests 
tojoinaswelL 

Executive and administrative affairs 

of the Council at large will be adminis- 
tered by a body comprised of the 
Chairman, Secretary and local area 
managers, whose duties will be to 
direct Council wide activities. What 
has actually been done by the "Blue 
Ribbon Committee" is to apply 
common modern business 
management technique to an amateur 
organization, thereby permitting local 
needs to be cared for on a local level 
while at the same time stressing the 
need for total unity on a statewide 
basis. It took the committee four 
months to prepare this report — four 
months of gathering information from 
all available inputs, looking carefully 
and evaluating the needs of different 
geographic locations and finally pre- 
paring all this data in a form that 
would make a truly workable new 




An WA6TK0 of Henry Radh dis- 
plays the prototype Kenwood TS-700 
2 meter All Mode Transceiver at the 
LERC Burbank Hamfest 



constitution acceptable to all 
involved. In October, they will meet 
again, this time to discuss the proposal 
and decide whether it is the route 
they wish to guide the future of 
CARC along. To my eyes, it seems a 
good foundation upon which to build 
a viable statewide organization, and I 
must commend those who gave of 
themselves for a job well done. If 
CARC can be reborn on a basis 
acceptable to all, then we are really 
going to have something out here* 

Where, then, does this leave the 
Southern California Repeater 
Association? In a resolution intro- 
duced for consideration on a basis 
parallel to that of the revised CARC 
constitution, the work of SCR A was 
noted and it was moved that SCR A be 
recognized as the Southern Regional 
Coordinator for 144/220 MHz (and 
that its elected chairman be con- 
sidered as fulfilling the duties of 
liaison coordinator with the CARC 
Executive Committee} , This too will 
be voted upon in October and the 
outcome of this vote will actually 
determine whether a working state- 
wide organization, responsible to the 
needs of all FM users, is possible. I 
sincerely hope that such an 
organization does come to pass. There 
is a lot more that I wish I had time to 
cover: the interesting discussion aimed 
at developing an official CARC 
response to docket 20282; the 
direction they voted to take in 
obtaining official FCC recognition for 
remote-base operation,* and a rather 
funny discussion as to where to hold 
their February '76 meeting. Can you 
believe that Tahoe lost to Los 
Angeles I I will try to cover more of 
this in greater depth next month, but 
at present wish to close by thanking 
Martin WA6T1C, who provided trans- 
portation, and Don WB6HJW, who 
recorded the meeting for me with my 
Panasonic RQ-309 cassette tape 
recorder. Since Saturday is a work day 
for me, this report would not have 
been possible without their kind 
assistance. 

I really had not planned on 

attending this year's LERC Burbank 
Hamfest but s& the event progressed, 
word kept filtering to me via two 
meters that Henry Radio was showing 
a new piece of two meter gear that 
would possibly revolutionize two 
meter operation. That I had to see, so 
I made the 15 minute drive to 
"Beautiful Downtown Burbank" and 

Continued on page f43 



134 



73 MAGAZINE 



Tht Uttimatt in SSTV Eqaipmuit 




SEEC HCV 3KB SSTV KEYBOARD 



Another first from the company and the 
designer of the world famous HCV-IB SSTV 
Caimra and tf*e HCV-2A SSTV Monitor, now 
the HCV-3KB Slow Scan TV Keyborad, This is 
the first commercially made SSTV Keyboard 
and it is built with the same quality as all 
SE EC/THOMAS equipment. We will not 
attempt to list all the features of the HCV>3KB 
here and we suggest that you write for full 
specifications. For those that are not familiar 
with SSTV Keyboards, the HCV-3KB 



eliminates the need for a menu board or other number/letter set-up arrangements which are 
very time consuming to set-up a meaningful text by arranpng letters one at a time, by hand on 
a board or other surface. It also "frees up" the SSTV camera for other uses, such as live shots of 
the operator or other subject matter. Simply type out the message you wish to send. 
#DD-0J54fi9 on file in US, Patent Office. AH American made 

- BASIC SPECfFICATlONS - 

• 30 characters per SSTV frame — 6 characters 

horizontally and 5 verticallv. Special 35 charac- 
ters per frame available. 

• Meets an standard accepted SSTV specifications 

• Positive-negative color (video) reversal 

• l4 and Vz frame rates 

• 4 shade gray scale generator 

• Dual fast and slow scan rf and video outputs 
(speciahoptionaO 

• Plug-in printed circuit board — gold flashed 
edge connector 

• ICs, op amps, transistors in plug-in sockets 

• Built-in 1 15V 50/60 Hz power supply 

• special ISV/' x 87=" x 3 %" aluminum cab- 
inet, black and white 




AUGUST 

SPECIAL 



— cash w/order price — $420 

(reg. $450) 



HCV-1 B SSTV Camera, w/lens & power supply . $425.00 (Reg. $450.00) 

HCV-1 B SSTV Camera with ALC, w/lens & power supply $450.00 (Reg. $480.00) 

HCV-2A SSTV Monitor w/2 CRT filters $360.00 (Reg. $380.00) 

HCV 28 SSTV Monitor w/ built-in Fast Scan viewfinder , .$455.00 (Reg. $480.00) 

HCV-70FSVFK Fast Scan viewfinda- mod Iff cation kit for 70 & 70 A, monitors , * $69.95 

,..,,.....*,. « * (Factory installation $37.50 additional! 

Sony TCI 1 OA Cassette Recorder • . . .....,,, $1 34.9! 

Heavy Duty Camera tripod , . , - . . , $34.95 



A complete line of camera and monitor accessories are avaOable — please write for current prices 
and delivery, complete specifications on any of our equipment or to be put on our mailing list. We 
have a 24-houT telephone answering ser\dce to better serve you, plus on the air technical assistance 
from the designer, WB4HCV (Jim), Two locations to better serve you — our main plant at 138-B 
Nauta-Line Drive and our tab at 218 Tyne Bay Drive^ Hendersonville* Complete 80-2 meter 
operation from either location. Drop in to see us if you are ever near Nashville, Tennessee! 

Write for specifications on our new sfow scan to fast scan/fast to stow scan 
monitor The HCV-2CS will have buHt-in 9'^ fast scan display, all necessary 
station interconnects in one unit, and much more. No assortment of black 
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master enlarge 



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price shown. Ail prices F^O,B, HendersonviUe TN. 




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' En6. Co.inc. 



P.O. BOX 572 

HENDERSONVILLE, TENNESSEE 37075 
TELEPHONE; 6158243235 



AUGUST 1975 



135 




T 1 ns 1 3 1 ! 
from page 132 



f «^ <1 I 1, I • t * t « 



£T//Efi TlfE UNIFIED FIFA.D? 

In the correspondence I have had 
on the subfect of Ether, the biggest 
question seemed to center on the 
efficiency of wave travel. 

That Ifght and radio waves can 
survive billions of years of travel from 
distant galaxies is a direct indication 
of the near perfect, if not perfect 
basic efficiency of their linear travel in 
space, the decrea&e of intensity being 
primarily a function of spheroidal 
dispersion* 

It appears that subatomic "parti- 
cles" are actuaHy somewhat similar 
energy- Ether motions trapped in cir- 
culatory resonances, the frequencies, 
number of wave lengths, direction of 
rotation and number of interlocking 
resonances setting the characteristics, 
such as mass, charge, polarity, life, 
etc. The more stable of these '*partf- 
ctes" continue in what amounts to 
perpetual motion, if billions of years 
qualifies them for that 

The importance of Ether is its being 
a perfect base for energy. Is the zero 
condition of the equation, E = Mc", 
fundamentally important and Ether? 
Is Ether the unified field? How test? 

D. H, Gieskieng W6NLB/7 

Box 386 
aarkdala AZ 86324 

Dave Gieskieng is tfw BUthor of 
*'Does Ether Cause Gravity?" in our 
May issue, and is now working on '^A 
Strip Chart Recorder for Everyor^*', 
-Ed, 



WONFIi REPORT 



I woufd like to report on 2 meter 
sideband activity here in southwestern 
Oklahoma. First of all, we are on 
using the KLM ECHO II, which 
checks out as a very nice rig* When I 
say we, I mean my wife Rosa 
WA4KBA as well as me. We are using 
2 KLM 9-eIen^nt beams up about 14 
meters and hear Oklahoma City every- 
time they are on. We normally operate 
on 145J10 and are listening all the 
time (squelch). We have ordered a 
lower sideband crystal from Inter- 
national and should be getting it 
shortly. KLM now has 144.0 MHz 
crystals in stock and we have ordered 



one of them as well. We are getting 
another ECHO II for the car and hope 
that we will have good luck with it. 

The conversion to both upper and 
lower sideband is very easy and you 
are able to bring the switch out to the 
front panel by using the test switch 
which is no longer needed with a CW 
plug in the back. KLM could probably 
give you a good report on the con- 
version, or as soon as I get the crystal 
and other parts I can. 

Rosa and I would like to see a lot 
more activity on 2 meter sideband and 
hope that the ECHO II and the ITC 
2000 will help. 

BobWillseyW4NUL/5 

Altus OK 

FASCtNATING SAGA 

* 

Just a quick npte to say that I think 
the April issue is one of the best 73s 
in the past year or so. It had a nice 
mix of articles, and I especially liked 
the article on the phone system. As a 
pilot for the Air Forcer I found W. S, 
Green's continuing saga fascinating. 
Some of the events I experienced at 
pilot training 50 years later sound 
very familiar. 

I would like to see an article on 
these small decoders that you usually 
see in your friendly neighborhood CB 
store for use with a police band 
receiver. They are simple enough for a 
CBer to install, and appear to be 
about S8 worth of parts usually sold 
for around $40, However, they do 
unscramble broadcasts^ 

Alan P- Biddle WA4SCA/5 
Jacksonville AR 

CULPRIT CAVGirr 



The attached for your perusal. Just 
cut it out of the ad section of one of 
our local papers. Use it as you wish, as 
I didn't know of a better person to 
send it to than you, as you have 
always carried the fight against CBen 
breaking the law as if there was no 
law. I was blamed for a lot of inter- 
ference to TV and hi-fi in the neigh- 
borhood, until I got all fired tired of it 
and started an investigation. To make 
a long story short, I found the culprit, 
a CBer a short distance from me who 
was opening an electronic garage door, 
wiping out TV pictures, including my 
own, and coming in "loud and clear" 
on the hi-fi's. Needless to say he is out 
of business per the FCC and he was 
running a 1000 Watt amplifier 5 
Watts????? He was taken to court but 






C B RADIO 

AM-SSB Midland Base with 
digital clock, sUder SSB kick 
desk mike; Kris (big 
boomer) Linear Amp. Both 
AM-SSB and receive pre 
amp, 300 watts AM4500 watt 
SSB ; mobile side bander II, 
AM-SSB plus 50-150 watt 
mobile linear. Palomar 500 
watt SWR (in line) monitor; 
antenna (1,000 watt) mast 
and coax; Solid State desk 
VHF receiver Hi-Lo bands 
FM, Police, Fire, Weather; 
antenna and coax included. 
Other goodies thrown in too. 
Talk to the world ! $900 takes 

all. 241-3413. 



don't know the outcome. However, 
we are no longer bothered with that 
bird and \ am no longer being blamed 
for any kind of interference. 

The nnag is swell and look forward 
to receiving it each month. Keep up 
the good fight, Wayne. It's a good 
thing that somebody has the "guts" to 
fight "city hall". It is just too bad that 
you don't get more support from the 
other publishers. 

Andy Anderson W6QV 
Sunland CA 

BUYER GUIDED 

Your article, "Which 2m Rig For 
You?", in the May 1975 issue of 73, 
was very good. 

I have been in the market for a new 
2m rig for quite some time and did 
not know exactly what to buy. 

After reading through your article 
several times, I decided a synthesized 
rig was just what I needed. Then it 
was just a matter of how much the 
pocket could afford, I liked the Clegg 
FIVf-27B, because of the independent 
receiver-transmitter frequency se- 
lectors. 

After scanning through my 73 mag- 
azine, I found one of your ads with 
the FM'27B on sate. 

Thanks to your article, I got the 
features I wanted in the 2m rig and a 
price to match. 

Now, to get maxium use from the 
2m rig, you will find a check for 
Si. 50 to cover the cost of your 1975 
Repeater Guide. 1 don't want to cut 
up my 73 Magazine for the order 

Terry Smock WAT RXF 
Springfield MA 

Continued on page 144 



136 



73 MAGAZINE 







Honestly, I don't want to be for- 
ever carping at ARRL, but dammit, 
they've gone and done it again! Before 
you chalk another one up to my 
constant criticism of the League 
(which I think Is utter hogwash, but I 
realize that my having the gal! to even 
mention the League in print is an 
affront to some of the more seriously 
disturbed ARRL followers), take a 
took at the facts. 



Fact 1: The board of directors 
decided, without consulting the mem- 
bers, to change the size of QST. This 
was not a modest change, but one of 
magnitude, bringing it from the size it 
has been for over 50 years up to 
Radio-Electronics magazine size 
(approximately]. Economy move, 
they said. 

Fact 2: The publishers of the other 
ham magazines have been trying for 




Oscar 6 Orbital Information 



Oscar 7 Drbital Information 



Orbit 


Date 


Time 


Longptude 




Oriiit 


Date 


Time 


Loni^tude 




(Aus) 


(GMT) 


ofEi|. 
Crossing ^W 


Made 




(Aug) 


(GMT) 


of Eq. 

Crossing "W 


12765 


1 


0135.5 


74.5 


A 


3237 


1 


0137,9 


74.3 


12777 


2 


0035.5 


59.4 


B 


3249 


2 


0037.3 


59.2 


12790 


3 


0130.5 


73.2 


A 


3262 


3 


0131.6 


72.7 


12802 


4 


0030.4 


58.2 


B 


3274 


4 


0030.9 


57.6 


12815 


5 


0125.3 


71.9 


A 


3287 


5 


0125.2 


71.1 


12827 


6 


0025.3 


56.9 


BX 


3299 


6 


0024.6 


56.0 


12840 


7 


0120.2 


70.6 


A 


3312 


7 


0118.8 


69.5 


12852 


8 


0020.1 


55.6 


B 


3324 


8 


0018.2 


54.4 


12865 


9 


0115.1 


69.4 


A 


3337 


9 


0112.5 


68.0 


12877 


10 


0015.0 


54.3 


B 


3349 


10 


0011. B 


52.8 


12890 


11 


0109.9 


68.1 


A 


3362 


11 


0106.1 


66.4 


12902 


12 


0009.9 


53.1 


B 


3374 


12 


0005.4 


51.2 


12915 


13 


0104.8 


66.8 


AX 


3387 


13 


0059.7 


64.8 


12927 


14 


0004.7 


51.8 


B 


3400 


14 


0154.0 


78.3 


12940 


15 


0059.7 


65. S 


A 


3412 


15 


0053.3 


63.2 


12953 


16 


0154.6 


79.3 


B 


3425 


16 


0147.6 


76.7 


12965 


17 


0054.5 


64.3 


A 


3437 


17 


0046.9 


61.5 


12978 


18 


0149.5 


78.0 


B 


3450 


18 


0141.3 


75.1 


T2990 


19 


0049.4 


63.0 


A 


3462 


19 


0040.6 


60.0 


13003 


20 


0144.3 


76.7 


BX 


3475 


20 


0134.9 


73.6 


13015 


21 


0044.3 


61.7 


A 


3487 


21 


0034.2 


58.4 


13028 


22 


0139.2 


75.4 


B 


3500 


22 


0128.5 


72.0 


13040 


23 


0039.1 


60.4 


A 


3512 


23 


0027.8 


56.8 


13053 


24 


0134.0 


74.2 


B 


3525 


24 


0122.1 


70.4 


13065 


25 


0033.9 


59.2 


A 


3537 


25 


0021.5 


55.2 


13078 


26 


0128.9 


72.9 


B 


3550 


26 


0115.8 


68.8 


13090 


27 


0028.8 


57.9 


AX 


3562 


27 


0015.1 


53.6 


13103 


28 


0123.8 


71.6 


B 


3575 


28 


0109.4 


67.2 


13115 


29 


0023.7 


56.6 


A 


3587 


29 


0008.7 


52.0 


13128 


30 


0118.6 


70.3 


B 


3600 


30 


0103.0 


65.6 


13140 


31 


0018.6 


55.3 


A 


3612 


31 


0002.3 


50.4 


AUGUST 1975 






- 






. 



years to get the League to shave 3/16" 
off QST so it would match the other 
magazines and made ad preparation 
less expensive for manufacturers. This 
would also, as has been pointed out 
many times, allow QST to fit modern 
web offset presses and allow com- 
monly available paper rolls to be used 
without excessive waste . . , permit- 
ting an estimated saving of $30,000 a 
year just on paper. 

Fact 3; Once a magazine fits web 
paper rolls and presses, the actual size 
of the magazine is irrelevant and it 
costs about the same per pound of 
nnagazine to print it This means that 
price wise there is nothing much to be 
gained from going to the 8-1/2" x 11" 
format over the present size of 73 
Magazine other than a loss of face in 
"going the 73 route." 

Fact 4: No mention was made of 
any decrease in QST subscription 
rates, so apparently there will be no 
savings to readers. On the contrary, 
there undoubtedly will be some extra 
money coming out of ham pockets as 
a result of this change. With the size 
of each page almost doubled, there is 
no question that the advertising rates 
will have to be raised sub- 
stantially , . . and this will inevitably 
force the prices of ham gear to In- 
crease* 

Fact 5: The bigger magazine won't 
match the libraries of ham magazines 
built up over the years- It will be 
thinner and floppier and won't stand 
up on a shelf. Stopping your sub* 
scription to QST won't solve the 
problem because the other ham maga- 
zines will be forced to change too, 
whether they like it or not, and all 
magazines will come in the unhandy 
giant size. 

So what are the benefits to ARRL 
members of this move by the 
board . . * a move made without con- 
sulting the members in any way? I 
have tried and tried to think of one 
single advantage to the reader of the 
larger magazine and I can't come up 
with one. 

So, before you put me down as 
carping, I challenge you to give me a 
good valid reason for the change, 

BYTE magazine will be published 
in the larger size, primarily because 
this will give more room for the large 
schennatics required for many of the 
computer circuits these days. No firm 
decision has yet been made on a 
change for 73, though I suppose we 
will have to go along in order to 
accommodate the new ad sizes. 

,_ WAYNE 



137 





m<S"s m(gIS nfflii®ir®ipir®(s®ss®!F 




^^ 



One of the most powerful micro* 
processor chips yet released has been 
announced by National ~ The PACE 

(processing and control element). This 
is the first of the 16-bit uP (is that a 
good abbreviation for micropro- 
cessor?) and it opens up a bigger and 
better world to the computer folk. 

The PACE chip opens up a new 
wave of panic for the computer estab- 
lishnnent in that it is the next big step 
in making computers drop substan- 
tratly in cost ... a move which 



threatens the whole distribution 

system set up to merchandise com- 
puters. While computers cost 
$100,000 or more, sales could effi- 
ciently be handled by a factory sales 
force ... with trained salesman 
making the sales. . . factory techs 
installing the system, and softwear 
firms aligned with that factory pro- 
gramming the installation. 

Part of this mystique resulted from 
the dominance of IBM (about 80% of 
the market) and their enormous profit 
margins. Other major manufacturers 




I 



PACE 



« i i 




'■■■■*! 
'■♦*«! 



Hill i null if Hi I 



This single 4% inch by 4% inch printed circuit card contains a compfete 
data pro{^ssing control/en At the heart of the system is PACE, a single-chip 
1 6-bit microprocessor devefoped by National Semiconductor Corporation. 
Other circuits on the board include four DS3608 hex MOS sense amplifiers 
and thme DM8097 fmx buffers below PACE, and the crystal osciUator and 
clock drivers above PACE. 



found that they had to offer at least 
as much sales fantasy as the meticu- 
lously trained IBM sales teams. Ditto 
for service, programming, etc. It was a 
hard act to beat, even with that gold 
mine of a markup in prices* 

Then came the large scale inte- 
grated computer chips such as the 
Intel 8008 and the 8080 ... the 
Motorola M6800 . . . and now the 
National PACE. Suddenly it was 
possible to make a central processing 
unit (CPU) which would do every- 
thing a small business could 
ask . . . not for S50,000, but for 
S5000 or perhaps even down to $500 
if the user didn't mind getting it in kit 
form. 

Computers are more than a 
CPU • . . you need something to con> 
municate with the CPU and some 
memory for the CPU to delve 
into . . , these are still costly, but they 
too are coming down rapidly . . . to 
the utter dismay of the computer 
industry. So far the result has been a 
nervousness, and myopia. Much of the 
computer industry has tried hard to 
ignore these new chips . . . the reac- 
tion seems to be that perhaps if they 
refuse to even read about them they 
won't exist and threaten the future. 

But peripherals are going down in 
price too, though not as f^t as CPUs. 
How long will it be before some chip 
company comes out with a single IC 
for a visual display terminal? There 
are about 60 ICs in the Southwest 
Technical visual display gener- 
ator • . * how long until this is one big 
chip? Memories are getting smaller 
and going onto chips too . , . and it 
only takes about eight of the new 
memory chips to give a computer all 
the memory it needs to work. 

The CPU has to take the input from 
a keyboard and sort the material out 
for suitable filing in the main memory 
bank . . . which these days is usualty a 
disk of some sort . . . floppy disk for a 
small amount of nnemory and a hard 
disk pack for bigger memories. A 
floppy disk will, for instance, hold 

Continued on page 144 



138 



73 MAGAZINE 



better 



SSTV Handbook (Second Printing) 

A brand new edition of the Sfow Scan 
Television Handbook has just come off the 73 
presses. This 250 page book covers slow scan 
like a blanket, starting from the basics and 
covering the latest developments. There are 
construction projects for building everything 
you'll need for good slow scan work. While 
manv of the new books coming out are priced 
almost beyond belief (one recent small **cook- 
book" was $15!), 73 has held down the price of 
the SSTV Handbook to just $5-00. Order this 
book today from 73 {$5 postpaid) or look for 
It at your locaf ham supptier* The Handbook 
was put together by two of the top pioneers in 
the field - Ralph Taggart W8SDQT and Don 
Miller W9NTP. 



Danger: Back Issues 

It has been brought to our attention that a 
large number of amateurs have been fired from 
their jobs and been divorced by their hitherto 
resigned wives — the trouble turns out to be in 
many cases tied to the receipt of a large bundle 
of back issues of 73 Magazine! Apparently this 
has caused the recipients to become so 
engrossed that they have essentially ^ost contact 
with the worfd. Severaf cases of near starvation 
due to aggravated engrossment have been 
reported. Authorities have been asked to 
prohibit the further distribution of back issue 
bundles of 73 on humanitarian grounds. Until 
these sJow-wftted authorities act, 73 has agreed 
to continue to ship these dangerous bundles — 
and at no increase in price , . , 25 back issues 
(our choice) $5.00 plus $1.50 for postage and 
handling. 



D SSTV HANDBOOK $5.00 ppd 

73 BACK ISSUES MIND BLOWER 

n Vintage Years $5.00 (shpg, $L50) 

n Mid-years 

n Recent Years 

Total Enclosed $ — 



Name. 



Address-. 
City 



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Signature 



^ State^ 



^ Zip. 



* Check 



Money Order 



MasterCharge if 

Bank Americard 4P 

Expiration Date 



&/7dfo: 73 Magazine Peterborough NH 03458 



12/24 HOUR 
6 DIGIT 
CLOCK KIT 
GIANT 
DIGITAL 
READOUT 

KIT INCLUDES: 

• Full, iflustrated P.C. Boards 

• (4) Giant .6 inch LED Readouts 
{DL-747) 

• (2) .3 inch Monsanto Man-7 

• National MM S314 Clock Chip 

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• Transistors, Diodes, Resistors, 
Capacitors, LEDS 

• Easy to Follow Step by Step 
Instructions 

• (12V AC Transformer Not 
Included) 



$29.95 



8008 

2102 

NE555 

NE-556 

NE-553 

NE-566 

NE567 

741 

309K 

LM 330 

LM-377/ 
2277 

PA 239/ 
2126 

n IW 

8038 
2N2222 

2N2907 

Jumbo 
LEOS 

Jumbo 
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Microprocessor 

RAM 

Timer 

Dual Timer 

Quad Timer 

PLL 

Tone Decoder 

Mint Dip 

Voltage Reg. 

Audio Amp 

Stereo Amp 

Stereo P re-Amp 
1 Watt Audio Amp To-5 
VCO (Intersil) 
Unbranded NPN 
Un branded PNP 

Red 

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N. J Residents Add 5% Sales Tax 08840 



N. J. 



AUGUST 1975 



139 



GATEWAY 

ELECTRONICS 



8123 Page Blvd. 

St. Louiii MO 63130 

(314)427-6116 



2839 W, 44th Ave. 
Denver CO 80211 
(303)458*5444 





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IC sockets may be assorted for quantity 
discounts. 1 to 9 pes. NET, 10 to 24 pes. 
LESS 5%, 25 to 99 LESS 10%, 100 to 
499 LESS 20%. WRITE FOR LARGE 
QUANTITY QUOTATIONS, D.LP. plugs 
and covers also available. 



* * * • 



MINIATURE 

THUMBWHEEL 

SWITCHES 



BCD ONLY ... 
COMPLIMENT ONLY 

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DECIMAL 

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HALF BLANK BODY 
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MINIATURE SIZE 0.315 X 1.3 X 
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A// switches are black with white 
Figures and snap-in front mounting. 



$5.00 minimum order —^ 

Please include sufficient postage. 

VISIT US WHEN fNST, L OUfS OR DENVER 






TWO NEW 



SUPER CIRCUITS 



*9V 



620 



R2 



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SIA 
0£ 




R5 TRI 
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lOOK 



EOL 

TlLa09 



Tra 




100 K tOV^ 



A 

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TIL 200 






BCiOT 



i 765 



12 34 



555 (TOPI 



Electronic egg timer. The IC functions as an of 
multivibrator which is controHed by the external 
tran^tor, Sla/b is the on-off toggle switch. (From 
Radio and Electronics Constructor, May, 1 975) 



*I2V 



TO Pdi LOWING l-F 




TO IF 



TO AC 
VOLTAGE 



MANUAL OAIN /h 
CONTROL 



nivtft 



T Type Attenuator This circuit, when inserted 
in between the stages of ^^ i-f amplifier, acts as a 
three section attenuator with a dynamic range 

beyond 60 dB. It can be controlled by a positive 
voltage from the AVC system or manually by use 
of a potentiometer. If AVC voltage is negative ^ 
substitute the NPN with a PNP transistor and 
transpose the collector and emitter connections. 
Don't forget to use a minus supply on the pot. 
Diode and transistor types are not criticaL Pin 
diodes are the best Original design used in present 
home brew receiver (From W6YUY) 



Further Revisions for 
''Scanning with a Syntheazer" 
(April, 1975, pages 23-36) 
Page 26 - Fig; 3. Unlabeled pin on IC39 is pin 
1, Add connection (where they cross) between 
wires IC20D, pin 9/IC29A, pin 13 and IC26B, pin 
5/tC19D, pin 10. Note: Where schematic shows 
'* — o" termination (e.g. IC36, ptn 3), connect to 
Vcc* 

Page 36 - Parts List, Control board: Push 
button for "Proceed" switch on Fig, 3 (CI 2) is 500 
pF, 

John Gearhart WA0AQO 

1408 Dawn Drive 

Columbia MO 65201 



140 



73 MAGAZINE 



Ron Fisher VK30M 
3 Fairview Avenue 
Glen Waverley, 21 50 
Australia 



Charge that KP202 



Bob Goullet VK3BU, 7 Drew Sl, East 
Keifof; 3042, has designed and con- 
structed a charging adaptor which most of us 
would find quite handy. This little unit is 
ideal if you already have a dc supply capable 
of delivering 15 to 18 volts at about 100 
milliamps. It would also be suitable to use 
with a twelve volt car system under charging 
conditions. Another source of voltage often 
found around the home Is junior's model 
train or slot car power supply. Make sure 
that the polarity is right and perhaps a series 
diode might be good insurance. Also, a 1000 
mF electrolytic across the output of the 
power supply would be worthwhile. 

The series globe in the adaptor serves two 
purposes. It acts as a charging indicator and 
also as a current limiter. In uperallon the 
rheostat should be adjusted so that the globe 
lights to about half brilliance with the 
batteries in a discharged condition. 

The mechanical construction of the 
adaptor should be fairly clear from the 
tl lustration. It was bent up from light gauge 
aluminum, and the contact studs are simply 
two 1/8 inch round head screws mounted on 
a piece of bake lite or similar insuiating 
material 

Another charger, designed by Don Paice 
VK3ADP, 21 Allister St,, MT Waverly, 31 49, 
IS completely self-contained with a built-in 
power supply. The mechanical basis of this is 
a medium size die-cast box with the KEN 





rOOJl 50mA 
WW LAMP 






+ 


J. r^ , 




Q 

■ 


14V 

ZENER n 
(OFTlOftlALr 




l.l (J 


15 TO fe 
VOLTS DC 


TO 

m CD*s 

— rfi 


rig. 1 


. NIC AD Charging Adaptor. 


\f 



holding bracket bent from a piece of perspex 
after careful heating with either boiling 
water or a blow torch. After attachment to 
the diecast box, the whole assembly was 
sprayed with silver enamel. 

Don's unit features quite a few deluxe 
items. Firstly, a micro switch in the ac line, 
actuated when the KEN is placed in the 
cradle. A small meter salvaged from an old 
Japanese tape recorder serves to indicate 
charging current The zener diode across the 






Reprinted irom Amateur Radio, Journal of the 

Wireless Institute of Austratia, August, 1974, 



The KP202 sitting in the VK3BU charging 
adaptor. 



AUGUST 1975 



141 



^^"^^ 




A close-up of the VK3BU charging adaptor. 




A close-up of the VK3ADP charger^ showing 
the ac micro switch actuator. 

output conducts when the battery voltage 
reaches 14 volts, and thus prevents over- 
charging. 

In conclusion, a few v^ords about charg- 



WiCROSWITCH 
(0PTI0NAL3 



Mr\jj- 



4 WO, 
50PIV 
1/2 A 




The KP202in the VK3ADP charger, 

ing nicads: 

When on charge, battery temperature 
should never exceed 38 deg, C. (1 00 deg, F). 
Check on published data for your 
particular batteries for maximum allowable 
charging current. 

The required charging time can be calcu- 
lated by dividing the amp*hour rating by the 
charging current, then multiplying this figure 
by 1 .25. 

Batteries in series should not be charged 
unless they are of the same type and in the 
same state of discharge. 

. . :VK30M 



IZOVAC 




HEQH 






-rp* SOPIV . 

12-ISV W- ^ 1/2 A ^ 

«I0VDC '^^^ 

m 



.12V 200mA TYPE W57 
TO LIMIT MAX CURftENT TO 50 m A 

lOOrnA 
[OPTIONAL ) 




Fig. 2. NIC AD PS for KEN KP202. 



142 



73 MAGAZINE 




Ottis Barron (KSBSE), Assistant 
Professor of Ertgirmering at the Uni- 
versity of Tennessee at Martin^ is 
teaching Genera/ and Advanced 
theory to the 11 new Novices of the 
Reef fool Amateur Radio Club and to 
oUier members interested in upgrading 
their licenses. The newfy formed club 
is one of the few throughout the 
nation with a college professor as an 
instructor. 

BE MY GOtST from page 7 

persons indk^ated an interest. 

The elates in code and theory were 
conducted twice a week for the next 
nine weeks and, when it was com- 
pleted, there were 1 1 new Novices* 

Once the Novices had their tickets, 
the three instructors feft additional 
help was needed in order to continue 
into the Genera) and Advanced fiefds 
and a nearby amateur, Ottis Barron 
K5BSE, assistant professor of 
electrical engineering at the University 
of Tennessee at Martin, consented to 
teach the classes without charge. 





Radio activities in Union City, Tenn. (pop. 13,500)^ lay dormant for years 
until earty this year when Willie Pope (standing ^nter) returned to the city 
and enlisted the aid of fellow ham Glen Leggett (starxiing left) and Bill 
Porter to help initiate Novice Radio Class instruction. Eleven persons have 
already pas^d their Novice tests and new classes wilt begin this fall with the 
goal of tripling the number of hams here within one yearns time. The new 
Novices are, from left: David Critchlow, Jr,, Herman Wi$mev\/$ki, Morris 
Mahan, Tim Fox, Mrs. Willie Pope, John Row, Jeff Row, Steve Harpole, 
Lance Hard, and not shown, Jody Harpole and Jerry Bennett. 



Within two months, Willie, who had 
held a Conditional for more than 15 
years, upgraded his class to Advanced 
— and three Generals also moved up 
one more rung on the amateur ladder. 

Now, within a few weeks, some of 
the Novices hope to try for their 

Generals and the newly formed 
Reel foot Amateur Radio Club is not 
only preparing to begin a new class in 
Novice, but has plans for booths at 



^ookmg 



from page 134 



West 



How do they pack so rmsch radio into 
so little space? 



afong with many other attendees of 
this event got a glimpse of the new 
Kenwood TS-700 multi-mode two 
meter transceiver 

The first thing that I noticed was 
that it did not look like the conven- 
tional two meter radio, but much 
more like a piece of HF gear. When it 
becomes available in the not too 
distant future, you will have one radio 
that will permit you to operate FM 
(simplex or via your favorite 
repeater), chat with those still on AM, 
or at the flip of a switch give you the 
ability to go hunting DX and the 
Oscar satellite on CW or SSB. You 
have a choice of either upper or lower 



two fairs, a hamfest, a picnic and two 

cam pouts. 

If the club meets its goal of 25 new 

hams in its area this year, the amateur 

population will have more than tripled 

in size, in the period of 12 short 
months* 

Talk's cheap — it's the action that 

counts, 

David G, Critchlow WB4CYX 

Managing Editor 

Union City Daily Messenger 

Union City TN 

sideband with built-in receiver incre^ 
mental tuning as an added feature, tf 
it sounds like the ultimate in a radio 
for two meters, be prepared to spend 
in the $700 to $900 bracket for this 
beauty* The TS-700 is dubbed the 
"All Mode 2 Meter Transceiver" and 
the quick glance I got of it teads me to 
believe that it will be well worth the 
bread. More on this as information is 
available; in the meantime I hope that 
the photos will suffice. 

Next month we will continue with 
more on CARC, coverage of the June 
21 SCR A meeting at J,P.L. in Pasa 
dena, and a story on the first repeater 
to go full time microwave control — 
all with photos I hope. Til! then 
goodbye from those of us who write 
for the 3:00 am shift in Los Angeles. 

..,WA6ITF 



AUGUST 1975 



143 



on goona djn ' - 




I Insist th 

from page 136 



w )i^^ 



1 



t:7 



HA VI NC A BA LL 



Considering I've received no re- 
sponse from any of the other pul> 
fications I've addressed similar cor- 
respondence to, your reply was both 
timely and appreciated. 

Therefore and henceforth, etc., 
please find one(l) each check in the 
amount of $4 for the back issues of 
Sept, Oct and Nov 1972 and any 
possible postage, etc. If you would 
ptease pass this request for back issues 
to inventory control (some fine 



people, I'm sure) I would be appre- 
ciatrve. 

I must say to you that in addition 
to having a fine magazine (although a 
bit short on HF) it was 73's fine 
technical publications that enabled me 
to get my first ticket while stationed 
on Okinawa (Conditional) and my 
upgrade to Advanced in March of this 
year. By the way, I got that first 
ticket in June of 74 and although 
electronics is my avocation I would 
never have made it to Advanced with- 
out 73's help. Thanks, I'm having a 
balL 

Richard E. Snider WA7YYA/4 

SSG, USA 
Warrenton VA 

Sergeant Snfder refers to a Wcfintcaf 
query he addressed to our editorial 
staff- Ed 



ARRL f'mRORY 



STOLEN: 2 meter FM transceiver 
consisting of VHF Engineering trans- 
mitter strip and 10 channel deck In 
black box mounted on top of 
Heathkit GR-llO scanning receiver^ 
with touchtone pad on transmitter 
Contact WA1UZE, 7 Gertrude Ave, 
Runford Rl 02916. 

TAKEN: FM transceiver. Regency 
HR2A with Topeka FM Eng. addi- 
tional 6 channel transmit conversion. 
S/N 04-07415, Contact W. H. 
Faulkner, Jr., W4D0, 6475 Chapman 
Field Drive. Miami FL 33156, 305 
666-9614. 

RIPPED OFF: Clegg FM 27B, S/N 
27053-1854, May 15, 1975. Contact 
W4PJG or Ft. Myers, Florida Police 
Department. Dr. Louis Persons 
W4PJG, Box 1647, Fort Myers FL 
3390Z 




The Hamburglcir 

STRIKES AGAIN ^ 



SWIPED: tCOM IC30A, S/N 
3803043. Contact Richard F. Helvey, 
2207 Central Ave No. 209, Billings 
MT 59102. 




AM 




Gerald J, Hughey 
107 New Street Apt 303 
East Orange (SIJ 07017 
(200 672-9276 

According to longstanding policy, 
73 Magazine makes a continual effort 
to n^tch those in need of technical 
help or instruction with those who 
feel they can offer it. If you find 
yourself in one of these two cate- 
gories« please do yourself and amateur 
radio a favor by contacting Ham Help, 
73, Peterborough NH 03458, 



Please add my name to your list of 
Ham Helpers. I have had CW, RTTY, 
AM, SSB, building, antenna and 
mobile experience, and would be 
especially interested in helping CBers 
get off 27 MHz and into legitimate 
radio. And t say that without malice 
towards any CBer who wants a ham 
ticket. 

Bob Isselhard K5INW 
2100 (SforthCielo 
Hobbs NM 88240 

I would like to offer my help to 
anyone needing help with home brew 
equipment, tube or solid state, and 
antennas and antenna tuners, 

Tom Cullen Jr. K1WXK/W1NXZ 

2 Westview Dr 
Wallii^fordCT 06492 



We think that the ARRL is making 
an error in holding its National Con- 
vention in Reston, Va. 

Reston, Va., has very restrictive 
antenna regulations and it does not 
allow outdoor antennas on its town 
houses (cluster housing). 

We feel that the League should not 
hold its convention in a community 
that is so hostile to amateur radio. 

Kay Alston WW3ZCE 
Nick Leggett WA3YFU 

Washington DC 



REALLY COOD 



II 



You might like to know that the 
Lake Amateur Radio Association, 
K4FC", has just started another 
Novice class, using Wayne's tapes — 
they're reafly good. 

Ken Aitken W4Fia 
Tavares FL 



NEW 




PRODUCTS 



from page 138 



about 3000 names and addresses for a 
mailing list. A hard disk can manage 
60,000 names! The CPU has to be 
able to print these out on a CRT or on 
a line printer . * , or a Teletype 
machine- The magic is in getting the 
names into and out of the memory 
quickly in whatever order you want 
them* 

If you are using the system for 
bookkeeping, then you want the CPU 
to be able to add and subtract for 
you. The programmer has to put 
instructions into the system which 
will tell it how to respond to the 
input * .. usually a keyboard. The pro- 
cess is not simple. 

Unless you are into computers, the 

great benefits of the PACE chip over 
the other microprocessors will be lost 
on you. It does have some sterling 
benefits . , . okay? 



OUR APOLOGIES. ,, 

To George Allen W1HC1 and VHF 
Engineering, for including incorrect 
pictures of the PS12C and PS24C 
power supply kits with George's 
recent New Product Review (July, 
1975, p. 147). Look for photos of the 
impressive real McCoys in an up- 
coming issue of 73 , , , 



144 



73 MAGAZINE 







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6883 B 


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4-1 25A 


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4h400A 


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COMMUNICATIONS, Inc. 

2115 Avenue X 
Brooklyn, NY 11235 
Phone (2121 646-6300 



SERIISG THE ISDUSTRY SiM£ 1922 




works 



The Calculating Counter 

NOAA FAX System 

0-60 MHz Synthesizer 

Remote Controlled RF Amp 

Plus MORE of 

The Oscar Zapper 

and 
K20AW's Digital 
SWR Computer 



APOLLO PRODUCTS by 'Village Twig 



ff 




1500X-2 
Rotary Antenna Switch 

Single pofe, 3 position An- 
tenna Switch • Low SWR • 
Use up to 30 MHz, 500 

Watt handling capacity. 
Sloping Front Console Cab- 

$12.95 




450X-S Antenna Switch 

3-Position Slide Switch 

Low Loss - Walnut grain 

Finish Chassis - Gotd Cover 

$5.95 
700X-2 KW Wattmeter 

Dummy Load Wattmeter for 
52 OSm Input. Measures RF 

in 4 ranges to 1000 watts. 

Measures modutation per- 
centage on calibrated scale. 
Portabfe. 

$124.50 




K 



Model 
"HA" 



DimensTotis 

eVa x3 15/32 x 7 1/16 
Si/sx 51/2x4 (Blank Panel) 
43^ x7% xll W/Handle 
11 1^ x6l4 X 12% 



Resale 

Net 

8.25 

8.95 

13.50 

20.50 




Meter 1 MA 

to fit "L" box 

ppd. 5,00 



"L" 

package enclosure 

"Shadow Box" machined 
with: 2-S0239, 1 - Pilot 

Light, 3 - Rocker 
Switches, and 2 - Knobs 

pkg. 29,95 



APOLLO PRODUCTS 





2100X-2 
SWR 

Bridge 

La rge 
Meter - 

Sloping Panel Cabinet - Rub- 
ber Feet - Keep m Antenna 
Line up to 1 Kilowatt 

$29.95 

90dX-2 
Wattmeter 

Measurs RF 
In 2 ranges 25 
and 250 watts. 
52 Ohm input. 

$29.95 
1700X-2 Vertical/ Hori- 
zontal Antenna Switch 

Allows operator to select 

any one of 3 antennas or 

dummy load. Two Antennas 

can be switched in 

simultaneously. New 

Sloping Front Console Cab. 

12.95 

WRITE FOR 

COMPLETE 

INFORMATION 

ON ANY OF 
THE ABOVE 



BOX 245 - VAUGHNSVILLE, OHIO 45893 • Phone (419) 646-3495 • Evening Phone (419) 646-3495 



146 



73 MAGAZINE 



Bob Lindecrantz K7PVZ 
14609 201 Avenue S.E. 
Ren ton WA 98055 



So You Want 



Front 



to 



Back Ratio ? 



It ail started on the drawing board with a 
5-element, widespaced beam —from 
theie to six; then the idea struck me to add 
two more elements — why not two reflec- 
tors. This started to get me in the ballpark. 
After trying a number of different spacings, 
and receiving reports from near and far on 
the changes, I arrived at the present design. 
I ran several constant checks with 
K7UWZ, Renton WA, W7WDZ, Bainbridge 

Island WA, and W7BVV, Salem OR. All 
reports revealed a front-to-back ratio of 48 
dB with little or no signal off the sides. 
Subsequent worldwide reports have been 
outstanding- I knew this was what I was 
looking for. 

The elements are 7/8 and 3/4 inch alumi- 
num tubing. The boom is three 10 foot 
sections of 2!4'* diameter aluminum. Each 
end is threaded so they can easily be joined 
together with a coupling sleeve, 

The driven element was cut and tuned for 
29 MHz using a grid dip meter at the 

element with the gamma discormected. This 

is one thing that most hams don't do, and 

this is the most important part of the 

antenna — to get that driven element on the 

resonating frequency. After the connection 

of the gamma to the beam and subsequent 

adjustments, the swr at this frequency was 

1.1:1. The rest of the elements were figured 

from the antenna handbook for 29 MHz. 



All three reflectors are the same length; 
the spacing of the reflectors was very critical 
as far as front *to-back ratio was concerned 
untU I arrived at the spacings as shown in the 

illustratiom 



f 



K 



f 



Pi 
m 



01 






a> 



1 



] } 



fv 



\ 



Al 






5Mo" 



Hm 6' 



Hi^*— 5' \0' 



C 



t 






^-^ 4' e" 



6^ 



t^4'€r 



€ 



]*-4'5^'Vm- 6' 



t 



1-^ 4'5"^ 



£' 



i^riREFLEGTOR 
ITS" 



-pf*- 4'n'- 



5 



3 DRIVEN EL£. 



J 5' JO* 



hH-*" 4' 8** -H 



3 01 
15*4' 



■*+*-4*€"-« 



202 
15* 



-H^4"53'^ 



y 



3 03 



14'n'* 



«-4'5'-^ 



3D4 
14" 10" 



=c 



1 



BOOM (0 SECTION OF TV MAST 
FOf? SPACmG OF 2 REFLECTORS 



THE 1 REFLECTORS ARE ALt 
THE S AME LEHGTH 17'B" 



Fig, I. End view of 3 reflectors. Note: The above 
spacing resulted in very, very good front-tos/de 
and front-to-back ratios^ 



AUGUST 1975 



147 



Now Two Great Ideas 
Got Their Start In Boston 



ham radio brokerage 




to SOll^ Call o<r write with a list of what you 
have TO sbW and how much ^om want for each 
item Include serial no s. age, condition, etc. 

to byy: Calf us. We'll put you in touch with 

someone selling what yoy'^e looking for in 
your vicinity. 




There iS never a chaise to the boyer for 
service. 



The selfer pays 10% of the asking price upon 
the sale of the equipmenL If no sale is made. 
the seller p^ys ncithing. 




call 

617-5368777 

WFSun12pm-6pm EST 
TThSat 6pm -12am EST 



or write 

BLJVERS £» SEi^LEHS 

Post Office Box 73 
Boston, Mass. 02215 



The mast for Ihe two reflectors is a 
10 foot section of TV mast mounted to the 
boom in the same manner as the boom is 
mounted to the mast. 

The spacing between the reflectors and 
the driven element is ,22 wavelength, and 
spacing between the driven element and 
director 1 is .17 wavelength; the remaming 
director are evenly spaced 4 '9*' on the 

boom. 

The boom length is 2 7 '5'' and each end is 
supported with nylon cord to a center mast 
to keep the ends from drooping. 

The antenna is 57* above the ground, and 
mounted on a crank-down, tilt-over tower. 

The gamma is out of the antenna hand- 
book. 

One other experbnent I ran was to extend 
the boom another five feet to add a ninth 
element (director). By doing this the results 
were about the same as with the eight 
elements — practically no improvement. 

With a little extra effort, you can be on 
the air with a high power signal running QRP 
power. 

. . ,K7PVZ 






VtfEIRNU 

COUTON , CALIFORNIA 92324 



<? 



)!^ 






DISCOUNTS 



il€!4 orders t«ke 5f| |30|- oilers tftke 10$; i60f oref«rp t«k« 15^; 11004- orders take Wi 



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7416 


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7417 


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7420 


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7436 


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.45 


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744t 


1*00 


7442 


.95 


7443 


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7Ufe 


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7446 


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7450 


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7454 


.35 


7460 


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7472 


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74I6I 

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74 1*^2 

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74196 

74200 

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74103 
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74L10 
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74L55 



.75 

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1.70 
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-30 
*30 
-35 
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• 30 
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.30 
,30 
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74L86 
74L93 
74195 

74Lge 

741X93 

76L13 
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74H0O 
74H04 
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74H30 
74H40 
74M60 
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309« 


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310H/N 


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311 H/N 


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312H 


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319H 


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32C8t 


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1*35 

.75 

.75 

2.25 

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2102K 7.75 

250IM 4.50 

252PN e,50 

2602Ji e,oa 

5007H 3,00 
501 OAH 3,40 
5013W 3.50 
5017N 2,95 
505eH 5.50 
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521JH 11,00 
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1. 4dd 50f Tor postage & h«MIir)g on ord^ri undtr flO, 

2. All it^ma guaranteed. 3, Sp«c 3h««ta 25# each. 

3. SE^TD YOUK ORBFH ALONG WITH CHFCK OR MONFT QftDfH TO: WEIRIIU, 
F.O* Booi 1307 > Coltoa, CA 92324 (Calif* resident 8 Includ* t% tax) 



eo*TON 


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CD4OOI 

CD4010 

CD4013 

CB4016 

CD4017 

CD4<K0 

CO4022 

CD4049 

CD405O 

74C157 

74CI63 

74CI63 

74CI64 

74C192 

74C193 
74C195 



• 50 

• 60 
1,45 
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1,50 

2.45 

1,25 
1.25 
2.10 
3.00 
3-15 
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5.00 
3^00 



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OOUCD 
0151CD 
0126CD 



9*00 
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9004H 
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952SM 

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1.30 

1.00 

1.00 

1,50 

2.90 

4,50 

4.25 

1,50 

.45 

• 65 



i 



148 



73 MAGAZINE 



THE ATLAS 210 AMD 215 

SOLID STATE SSB TRAMSCEiVERS 




Ifi 



This may sound like just another catchy headline, but this is 
the best, and quickest way we can think of to describe the 
Atlas transceiver. 



For mobile operation all you have to do is make a 
one time installation of the Plug-in Mobile Mount, 
and thereafter, when you want to operate mobile, 
just slide your Atlas transceiver into the mount. 
All connections are made automatically, as 
shown below. It takes only seconds, and you are 
ready to operate. Fixed station operation is 
achieved in the same easy manner, since the 
Atlas AC Console has the same plug-in system 
as the mobile mount. 



No Transmitter Tuning! 

This is another outstanding feature of the Atlas 
transceiver. There is no transmitter tuning what- 



soever. This permits instant QSY or band- 
switching. Simply tune in to your frequency and 
GO! 

No other rig on the market will provide you with 
so much operating pleasure. 

When you combine the simplicity of operation 
with unparalleled selectivity, immunity to cross 
modulation or overload, solid state reliability, 
200 watts R E.P input pow/er and 5 band cover- 
age.. .the Atlas 210/215 has everything you 
could want in a transceiver. 

Model 210 covers 80 through 10 meters. 
Model 215 covers 160 through 15 meters. 



Plug-In and GO! 



$599 




AMERICAN MADE AND GUARANTEED BY: 



k^ U ^A 



417 Via Del Monte Oceanside. CA 92054 



Available NOW at your Atlas dealers. See 
him for complete details, or drop us a card 
and we'll mail you a brochure and dealer 
list. 



p 



I 



♦:♦:♦:♦:♦:♦:♦:♦:♦:♦:♦:♦:♦ 



Caveat Eiptor? 



♦:♦:♦:♦:♦:♦:♦:♦:♦:♦:♦:♦:♦ 



PRICE - $2 per 25 words for nan<on> 
mercial ads; S10 per 25 words for bus- 
iness ventures. No display ads or agency 
di&coum. Include your check with order. 
Deadline for ads is the 1st of the month 
two months prior to publication. For 
examples )*inuary 1st is the deadline for 
the March issue which will be maited on 
the Ifhh of February, 

We will be the judge of suitability of ads. 
Our responsibility for errors extends only 
to printing a correct ad in a later issue. 
For J1 extra we can maintain a reply box 
for you. 

MANUFACTURERS, Distributorsl 
The Memphis Hamfest will be bigger 
than ever. The dates are Saturday and 
Sunday October 4 and 5. Best loca* 
tioo possible - State Technical Insti- 
tute, Interstate 40 at Macon Road, 
Security. Contact Chairman, Harry 
Simpson W4SCF, Box 27015. 
Memphis TN 38127, phone (901) 
358-5705, 



TWO FLASTU; HOLDKRS FRAME 

and display 40 QSL's for $1.00 or 7 
holders enhance 140 cards for S3, DO 
- from your Dealer, or prepaid direct: 
TEPABCO, Box 198M/ Gallatin, Ten- 
nessee 37066. 

R-390A/URR ~ like new, recent over- 
haul with manuals and connectors. 
$500. WA1TEJ 603 880-2788 days. 

AN/FGC-20 - RTTY TT^100/FG 
Kleinschmidt printer, like new, with 

table, 60, 66, 75, 100 gears and 
manual. S150. WA1TEJ 603 

880-2788 days. 

STANDARD 830 L 3 Hi band 3 chan- 
nel 2 Watt HT less accessories. SI 00. 
WA1TEJ 603 880-2788 days. 

SNOOPERSCOPE M~3-20KV infrared 
seein-the-dark telescope in excellent 
working condition with power supply. 
SI 50, WA1TEJ 603 880-2788 days. 



ASSEMBLED PCB 
$24.95 ppd 




^SELF-COMPLETING DOTS AND DASHES 

■ INSTANT START WrTH JAM PROOF SPACING 

• BUILT-IN SIDETONE 

•5^50 WPM 

•OPERATES ON 5-12 Vdc 

*FOR GRID-SLOCK AND CATHODE KEYING 

'SIZE 2-3x3.5 INCHES 

(Wl residents add 4% sales tax) 

DGM ELECTRONICS 

787 Briar Lane, Beloit, Wl. 53511 




HALL OF FAME HAMFEST and 
auction ratn or shine, Aug 3, 1975, 
Canton, Ohio. Come to Canton for 
football's greatest weekend. Satur- 
day's activities - parade, enshrine- 
ment, NFL game Cincinnati vs Wash- 
ington, Sunday — hamfest and auction 
at Stark County Fairgrounds* Main 
prizes - ICOM 230 - Hallicrafters 
FPM 300 - Standard 2 mtr hand held. 
Motet and camping space available. 
Call WF8H0F 146.19/79 or 
146.52/52. Further information write 
WA8SHP, 73 Nimishnian St., Sandy- 
ville. Ohio 44671 or call W8SWB 
(216) 455^4449, 

WANTED - Make, Model and Serial 
number of stolen ham gear for big list. 

W7UD, 3637 West Grandview, 

Tacoma WA 98466. 

AN/URA-BA - complete RTTY 
diversity group: 2 CV-89A/URA'8B 
converters, CM'22A/URA-8B compar- 
ator, MT-719/URA-8B cabinet, con- 
nectors and manuals all like new. 
S25a WAITEJ 603-880^2788 days. 

SWAN, CushCraft at prices I dare not 
publish. Cat! or write WONGS, Bob 
Smith Electronics, 1226 9th Avenue 
North, Fort Dodge I A 50501. (515) 
5763886. 

Continued on pam f52 

CURTIS KEYER 



CHIP 



as low 
as 



$7.95 



# * 



m. t * * * 



• » 1 



* * # 



« '■ 



• * * 



$ 24. 9S 
$ 49.95 
$ 1.50 



8043; iG only, 50* up group rate 
8043-1; IC, PCB. Manual 

8043-2; Seml-ktt 

Add for air postage and handling . 
(See Feb 75 CQ and Apr 75 HR articles) 
KB42Q0 Keyboard Keyer {Oct 74 OST) . 
EK420/KM420 Keyer/Memory (Oct 73 QST) $439. 

EK430 CMOS Keyer (uses 8043 chip) 
IK440 Instructokeyer (Jun 75 '73") 

CURTIS ELECTRO DEVICES. Inc 

(415) 964-3t36 
Box 4090j ftountalfl Vie w. Cal. 94040 



m * * * • 



$549.95 

$124.9 
$224.95 




I 




MINIATURE 

SUB-AUDIBLE 

TONE 

ENCODER 



•Compaiible wtth all sub audible tooe systems such a% 
Private Line, Channel Guard, Quiet Char^nel, etc. 

•GiS5s Epoicv PCS, s*licon transistors, and tantalum electro 
I V tics u^ed throughoyt 

•Any mmiature dual col! contactless reed may be used 
(Motorola TLN6824A, TLN6709B - Bramco RF 20) 

•Powered by 12vdc @3ma 

•use on any tor»e frequency 67Hz to 250H2 

•Minraiure in size 2, 5k. 75x1 .5'^ high 

• Wifed and re&ted .,.,... $14.95 

•Complete less reed (Ai^ajJable in 33 freqs. tor Si 7.50 ©a/ 

• Output 3v RMS sir^ewai/e, low distort*«n 

• Postpaid — Calif, residents ^d b% ^ales tax 



COMMUNICATIONS 
SPECIALISTS 

P,0. Box 153, Brea CA 92621 



KAUFMAN BALUN 



KAUFMAN 

water tight 
BALXm 



new and improved 

molded plastic 




with or 
without 
BALUN 

1:1 impedanct 

match 



Patent No, For drpofes, 
D219106 beams, inverted "V'\ and quads 

KAUFMAN Center InsMlatOr with BALUN S12.S0 postpaid USA 

KAUFMAN Center Insulator without BALUN 7.S0 postpaid USA 

Dragon Ry anienna con^i/ucUon sheet and drawing S2.S0 postpaid USA 



3 Kw PEP 

4 Ounces 
Ql Ferrite 



KAUFMAN INDUSTRIES 

BOX 817 
REEDS FERRY, NH 03054 



150 



73 MAGAZINE 




i 





Argonaat 



Model 405 Lineftr 



SPECIFICATIONS 



ARGONAUT, MODEL 505 

GENERAL: Covers al! AmaJeur bands tO-SO meters. 9 MHz crys- 
tal filter 2-5 kHz bandwidth. tJ shape factor @ 6/50 dB points. 
Automatic sideband selection, reversible- Solid slate design. Per- 
meability tuned circuits. Sev^n plug-in crrcuit boards. Direct fre- 
quency readout. Vernier tuning. Dial accuracy ±: 5 kHz (slightly 
more at 10 meters). Drifl less than 100 Hz. Power required 12-15 
VDC @ 150 mA receive. 800 mA transmit at rated output. Con- 
struction: aluminum chassis, top and front panel, molded piastic 
end panels. Cream front pane), walnut vinyl top and end trim- 
Size: HWD 4y^'' X 13" X 7**, Weight 6 lbs. 

RECEIVER: Sensitivity less than V2 uV for 10 dB S + N/N. "S" 
meter. AGC Offset tuning. Tuned MOSFET RF amplifier and 
mixer Audio distortion less than 2%- Internal speaker. Head- 
phone/ externat speaker jack. 

TRANSMITTER: 5 watts input power. Broad band final ampfifier 
eliminates tuning. 50-75 ohms output impedance. PresS'to-tafk. 
Instant CW break-in. SWR bridge integrai TVI filter. CW sidetone. 
Integrated circuit balanced modulator. Automatic CW offset of 
approximately 700 Hz, Shaped keymg. 

LINEAR AMPLIFIER. MODEL 405 

Covers all Amateur bands 10-80 meters. 50 watts oulput power, 
contrnuous sme wave. Broad band design eliminates tuning. Less 
than 2 watts of drive required. RF wattmeter SWR meter. Exciter 
actuated antenna changeover. Front panel T/R time delay con- 
trol* Individual band-switcHed tow pass filters. TVI filter. Two 
plug-in circuit boards. Computer estimated life of output tran- 
sistors 25.7 years- Power required 12-15 VDC @ 8 A. max. Con- 
structFon: aluminum chassis, top and front panel, molded plastic 
side panels. Cream front panel, walnut vinyl top and end trim. 
Size: HWD 4y2'' x 7" x 8". Weight aVa tbs. 



TUFTS 




Electronics 



386 Main St., Medford, Mass. 02155 

617-395-8280 
NEW ENGLAND'S EXCLUSIVE DEALER 



AUGUST 1975 



151 






Caveat Emptor 






from page iSO 

FB CONDITION SBE-34ACDC trans- 
ceiver $195, HRT-2 Regency HT W-4 
rocks, cost $200 plus. (Sell 4 SI 45.) 
Kenny, 455-41 st Ave., SF 
415-386-6313- Hot Water 17A with 
FM-adapter 2m transceiver. Visit Sing- 
apore . . , the best Country in the 
WORLD. 

SSTV MONITOR, W6MXV, PC 
boards factory checked, with extra 7" 
CRT and 2 cassettes - S85.00 - you 

pay shipping. WA4TST, 507 Pinecone 
Street, Waycro^ GA 31501. 

TECH MANUALS - $6,50 each: 
R^220/URR, SP-600 JX, USM 159, 
GRR-5, URM-25D. Thousands more 
available. Send 50rf (coin) for large 
list. W3IHD, 7218 Roanne Drive, 
Washington DC 20021. 

FOREIGN LANGUAGE cassettes. 2 
— 60 minute quality tapes per set 
French, German. Italian, Spanish. S6 a 
set, 4 sets $20. Royal, Box 2174, 

Sandusky, Ohio 44870. 



CINCINNATI HAMFEST: 38th 
annual — Sunday, September 21, 
1975 at the New Strieker's Grove on 
State Route 128, one mile west of 
Ross (Venice), Ohio. Flea market, 
contests, model aircraft flying, food 
and beverages all day. Advanced 
tickets $7, covers everything; $8 at 
gate. For tickets or further informa- 
tion: Carl J, Dettmar WBNCV, 8630 
Cavalier Drive, Cincinnati OH 45231. 

FM RECEIVER, preamp, scanner, 
UHF converter kits. Hamtronics, Inc, 
182 Belmont, Rochester NY 14612. 



WARREN HAMFESTf Sunday, 
August 17, Yankee Lake, Ohio. On 
Rt. 7, five miles north of 180. Dealers' 

displays. Swimming and picnicrng. 
Giant flea market (Vendor's fee: 
SI -00 plus registration), A $3.00 regis- 
tration includes: Door prize, Main 
prize, and XYL tickets. More info: 
Hamfest, PO Box 809, Warren OH 
44482. 

WANTED used Bruel and Kjaer audio 
test equipment measuring amp, 
^jectrometer. pistonphone, hearing 
aid test box, chart recorder. Contact 
Bob Sumption, Berrien County Day 
Program for Hearing Impaired 
Children, Sylvester Boulevard, Berrien 
Springs, Michigan 49103. 



STANDARD 840ZA carrier squelch 
pocket paging receiver, like new, now 
on 154.19, With charger and spare 
nicad. SI 25. WA1TEJ 603 880-2788 
days. 

VERY INTERESTING! Next 5 issues 
SI. "The Ham Trader/' Sycamore IL 
601 78. (Ask about our "HAM EQUI P- 
MENT BUYERS GUIDE" covering 
receivers, transmitters, transceivers, 
amplifiers 1945-75, Indispensable!! 

FOUNDATION FOR AMATEUR 
RADIO annual Hamfest Sunday, 19 
October 1975 at Gaithersburg Mary- 
land Fairgrounds. 

GE - PREPROGRESS 450 MHz base 
station transmitter with oven and 
power supply, 12 Watts out, 
4ET19A1. $25. K, Basett, 1124 
Wood row Ave., Waynesboro VA 
22980. 

POLICE AND FIRE Scanner Special 
- Regency ACT - R - 10 H/L/U 10 
channel 3 bands, combined ac/dc 10 
free crystals included SI 69.00 pre^ 
paid, dealer inquiries invited, Four 
Wheeler Communications lO-F New 
Scotland Avenue, Albany NY 12208. 

Continued on page 154 




some people 
talk power - 

we 
deliver it« 



VHF Class C 
Power Amplifiers 

• Superb Craftsmanship 
State of the Art Performarjce 
^Futf One Year i/\/arranty 

MODEL PI 5A1 - 1 3 W input 1225 W output, 
1 3,6 V at 2 Annps $55 ppd. 

MODEL P50A1 - 1-3W input 40-60W output. 

1 3-6 V at 8 Amps $139. 

MODEL P50A10 - 1.5-15 W input 1265 W 
output. 13.6 V at 6 Amps $98 ppd. 

MODEL P100AS - 2-5 W input 60-1 OCK W 
output. 13.6 V at 14 Amps $198 ppd. 

MODEL P100A10 — 3-10 W input 60-1 0O+ W 
output. 1 3*6 V at 1 4 Amps $198 ppd* 

MODEL P100A20 - 15-30 W input 7&^1 00+ W 
output, 13.6 V at 14 Amps $155 ppd. 

M-Tech Engineering, Inc. 

Box C, Springfield VA 22151 (703) 354-0573 

M-TECH . . . The Quality Company 



NOW THE AMATEUR 
CAN BUY COMMERCIAL QUALITY 

SSB EQUIPMENT 

(Preserrt users include foreign 
government agencies) 



«3Nrtl 



CR 




Solid State 2-30 MHz Linear Power Amplifiers 

1. CR250AA; 250 to 400 Watts P.E.P. input 
power with as little as 2 to 5 Watts drive. 

12VDC. $299.00 

2. CR500AA: 500 to 700 watts P.E.P. input 
power with as little as 4 to 10 watts drive. 
1 1 5/230 VAC $599.00 

Also 20 watt P.E.P. Walkie Talkje, 400 to 
600 watt monobanders, receivers and multi- 
band transceivers, VHF-FM Mobile base and 
repeaters. We accept Master Charge, BankAmer- 
icard or certified check on mail orders. Please 
Inciude charge cards account number and expir- 
ation date. 




electronics 

1169 Chess Drive, Unit G 
Foster City, Ca. 94404 



152 



73 MAGAZINE 














The front panel and control locations have been changed to make 

the IC-22A even better looking and easier to operate. The new 

design allows the use of larger channel numbers which may be 

viewed from the left side or right side by reversing the window position and installing a new 

dial [optional at nominal cost) 

Inside is the same high quality radio construction and engineering that has made the IC-22 the 
most reliable, most popular two meter crystal controlled set on the market. 
When you join 22 channels of capacity (five supplied) with the unexcelled performance of 
helical RF filtering in the receiver front end then add solid state T-R switching you get one 
great radio for your money. All the great features that made the IC-22 so desired are still 
there. Including, 1 watt 10 watt switch option, trimmer capacitors on both receiver and 
transmitter crystals plus a 9 pin accessory jack with the discriminator already wired for 
frequency calibration 



New and Used Equipment 





59th & South Penn, Oklahoma City, Oklahoma 

See us at Oklahoma Ham Holiday and State ARRL Convention Aug. 2-3 

South Gate Inn 1-35 at S.E 51^^ 



AliaiJ-ST 1975 



153 






Caveat Emptor 






from page i52 

MEMPHIS is beautiful in October! 
The Memphis Hamfesi, bigger and 
better than ever, will be held at State 
Technical Institute, Interstate 40 at 
Macon Road, on SaturdaY and Sunday 
October 4 and 5. Demonstrations, 
displays, MARS meetings, flea market, 
XYL entertain n>ent, prizes. Informal 
dinners Saturday night. Dealers and 
distributors welcome. Talk in on 
3980, .34- .94 and MARS. Contact 
Harry Simpson W4SCF. Box 27015, 
Memphis TN 38127 or telephone 
19011 3585707. 

FOR SALE: Clegg 66er BRAND NEW 
6 nyeter 117V ac & 12 V dc. Built-in 
P.S. and ManuaL $120 + UPS. Heath- 
kit SB301 w/filters, SB6O0 SB401 
w/xtal Pack & Manuals Mint S460.00 
+ shipping. Henry 2K4 linear amp 
console mint $585/00+ shipping. J.A. 
La Torre, P.0, Box 521 G, Lawrence 
MA 01842. 

F.R,R,L. H AMP EST - August 17th, 
U.S. Rt. #30 East of Aurora, ML 
Phillips Park - Picnic - Zoo - Family 
Fun. Advance Donation $1.00, $1.50 
at Park, S,A,S,E, to P.O. Box 443, 
Aurora, 60507. Two Grand Prizes and 
many others. 

NO DX QSLs? Try ham sentences in 
54 languages on your card! "K3CHP's 
DX QSL GUIDE/' $3.95. Joe 
Mikuckis, 6913 Furman Pkwy,, River- 
dale MD 20840, 

WANTED: Full correspondence 
course of computer digitals and ICs 
from someone who has moved up in 
the field. State price. Cyril Lievesley, 
142 Brightman St., Fall River MA 
02720, 



FREE: 8 EXTRA CRYSTALS of 
your choice with the purchase of a 
new I COM IC-22A at S249. With the 
10 crystals which come factory- 
installed in the IC-22A, this gives you 
a total of 18 crystalsf For equally 
good deals on Kenwood, Drake, 
Collins, TenTec, Swan, Atlas, Mid- 
land, Standard, Regency, Tempo, 
Alpha, Genave, Hy Gain, CushCraft, 
Antenna Specialists, Hustler, Mosley 
and others, write or call HOQSIER 
ELECTRONICS, your ham head- 
quarters in the heart of the Midwest, 
and become one of our many happy 
and satisfied customers, Hoosier Elec- 
tronics, P.O. Box 2001, Terre Haute, 
Indiana 47802. (812) 894 2397. 

THE ORIGINAL FM Hamfest Aug, 3, 
1975, near Angola, Ind. Free flea 
market^ picnic grounds, swimming, 
boating available. Talk in on 
146.16 76, 146.94. For information 
contact Fort Wayne Repeater 
Association, Box 6022, Fort Wayne, 
I N 46806. 

WANTED: Mobile telephone equip- 
ment such as Deico, GE, etc. Also 
heads, decoders, duplexers. Greg 
Hyman, WA20TG, 19 Sicard Ave., 
New Rochelle, New York 10804, 
(914) 636-2494. 

GPL - TELEVISION SYSTEM, 
PD150 camera with lens and book, 18 
inch Conrac monitor. $140, K, 
Bassett, 1124 Woodrow Ave., 
Waynesboro V A 22980. 

WANTED to buy - TRIBAND 
ANTENNA. FOR SALE - TR106 & 
VFO S75.00; Clegg FM27B & AC 
$250,00; Ctegg Mark II SI 50.00. 
Ameco TX62 $40,00. Swan 35Q/AC 
and upper lower sideband adaptor, 
VOX, and factory installed VFO. All 
guaranteed perfect condition. Duane 
Kilbourn, 17100 14 Mile Rd, Battle 
Credc Ml 49017. 



500 MHZ PRESCALER 

Extend the range ol your present frequency counter 
to measure through 500 MHZ (typically 525 MHZ) 
Works into any standard counter rated for 5 MHE or 
higher A must tor work on 2 meters. 432 MHZ and 
commercial high bands 
*150 nnv sftnsiuvfty 

•tnput overload protectod 

•50 ohm Input Z 

•Small size 
2 3/4 I 2 1/8 % 1 5/8" 

•BNC connectors 

•Divide by 100 or 10 

•Light blue case 

•Model Ps 2A S99 95 

Prescaier is shipped assembled, tested and ready to 
operate. Complete with line cord power suppiy 

DAVIS ELECTRONICS 

636 Shertdan Di , Tonawar^da, NY 14150 716 874 BS^B ^ H 




AN OFFER you can't refuse - 
BUYERS & SELLERS P. 148. 

RADIO ARCHIVES, amateur ANEC- 
DOTES (then & now) solicited for 
proposed (SASE subscription} 
monthly PR newsletter. Electronic 
Avocations, 3207 fourth St. N., Mpls., 
Mn. 55412. 

THE 28th ANNUAL Turkey Run 
Hanrifest and VHF Picnic sponsored 
by the Wabash Valley ARA, Inc. will 
be held Sunday, July 27, at Turkey 
Run State Park near Rockville, 
Indtarra. Don't miss the midwest's 
finest flea market. XYL Bingo, re- 
freshments, camping facilities and 
park recreation for the kids. Also this 
year, banquet July 26, 7:30 pm 
featuring guest speaker W9NTP, in 
park dining halL Banquet by reserva- 
tion only, S6,50/person: reservation 
deadline Juty 1. Activities begin 9 am 
Sunday, talk^in 146.94 W9UUU/a 
For details, ttckets and banquet reser- 
vations SASE WVARA Hamfest, Box 
81, Terre Haute IN 47808. 

HAMFESTERS 41st Hamfest and 
Picnic, Sunday August 10, 1975, 
Santa Fe Park, 91st and Wolf Road, 
Willow Springs, Illinois, Southwest of 
Chicago. Exhibits for OMs and XYLs, 
famous Swappers Row. Information 
contact John Raiger K9DRS, 8919 
West Golfview Drive, Orland Park, 
Illinois 60462. Tickets write Josepti 
Poradyla WA9IWU, 5701 South Cali- 
fornia, Chicago, Illinois 60629, 

HP-65 USERS exchange ideas, pro- 
grams, methods. Monthly newsletter; 
Request information and sample 
nev^letter, Richard Nelson, 2541 W, 
Camden PI, Santa Ana CA 92704. 

MOTOROLA HANDIE-TALKIE 
WANTED, Also want accessories, 
Sidney Helperin, 5046 Veioz Ave,, 
Tarzana CA 91356. (213) 345 6760. 



TELETYPE 



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CW IDER - AK-2 AFSK ^ XK-2 XTAL AFSK 
- and LOTS MORE. 

CALL OR WRITE FOR DETAILS AND PRICES 

Electronic Development; Inc., P,0. 
Box 951, Salem, Oregon 97308 (503) 
399 9660. 



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THE f€0«(MCiL APPflMCH TO AMATtUR TlLt- 
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154 



73 MAGAZINE 




CALGARY ALBERTA 
AUG 1-3 
Century Calgary Amateur Radio 
Convention — CARF National and 
ARRL Canadian Division Convention^ 
Speakers include astronaut Dr. Owen 
Garriot K5LFL (Sky lab 3, 24.4 mega- 
miles in 59 1/2 days orbiting Earth}, 
Martin Laine 0H2BH - DX, Larry 
Kayser VE3QB - AM SAT, Lew 
McCoy W1ICP - ARRL - quads and 
humor, Dr. F. Green VE3I0 - D.O.C, 
— on interference. Dr. J. S. Belrose 
VE2CV - D.OX. - antennas, Dr, E, 
Hara - D.O.C, - fiber optics. Bilt 
Porter W3AAC-K1YPE/VE3, US 
Ambassador to Canada, has also been 
invited. 



Pre-regtstration S5 til end of June; 

registration at door S7.50 starts at 
noon August 1. Various special 
interest breakfasts, luncheons and 
tech sessions Saturday, August 2. Ban- 
quet S14.50 with K5LFL talk. Tech 
sessions Sunday also. The convention 
will be held in the Calgary Inn; rooms 
available at 1973 rates (S20'25 com- 
pared to $30 38). Camping available 
north and west of town. Info write 
Convention '75, Box 592, Calgary, 
Alberta T2P 2 J 2, 

TEMPLE TX 
AUG 13 

The Texas VHF-FM Society will 
hold its Summer Convention 1975 



Aug 1, 2 and 3 at The Ponderosa Inn 
in Temple, Texas, This year's conven 
tion will be the best ever with the 
featured speaker Mr A. Prose Walker, 

Chief of the Amateur and Citizens 
Division of the FCC. There wilt also 
be equipment dispfays, technical 
sessions, a swap-fest, ladies activities 
and many, many prizes. For more 
information contact the Temple VHP 
Repeater Association, PO Box 23. 
Temple, Texas 7650 T 

WINCHESTER VA 
AUG 2-3 

The Shenandoah Valley Amateur 
Radio Club will present its 25th 
Annual Hamfest in Winchester, 
Virginia, on August 2nd and 3rd, 
1975. The festivities start Saturday 
night at the Lee Jackson Motor Inn 
with the Social Hour beginning at 6 
pm. Buffet-dinner wifl be served at 7 
pm, after the dinner there wilt be 
guest speakers and musical entertain- 
ment Dinner — $6. Flea market starts 
Sunday 10 am till 4 pm. Registration 
tickets are S2 or 35 for 3 tickets or 
S10 for 10 tickets. For more informa- 
tion contact the Shenandoah Valley 
ARC, Box 139, Winchester VA 
22B0T 

Coffttnued on page fS6 



1/2 KW 

WIND 

ELECTRIC 
6ENERAT0R 





NEW KIT INCLUDES: 

BLADES 

SPECIAL ALTERNATOR 
CONTROL UNIT 
FABRICATION INSTRUCTIONS 

BASIC KIT AS LOW AS: 

$14700 

Standard Research Incorporated 

p. O. BOX 1291 
east LANSING. MICH. 48823 



SWB-2 $22.95* 

SWR BRIDGE READS FORWARD & 
REFLECTED POWER SIMULTANEOUSLY 

'EASY READ' METERS 
DUAL lOO-MICROAMP METER MOVEMENTS 



LOW INSERTION LOSS 



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MAY BE LEFT IN LINE UP TO 2,000 WATTS 

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* prices subject to change without notice , . . 

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AUGUST 1975 



155 



MOnE 




OKLAHOMA CITY OK 
AUG 2-3 

The Oklahoma Ham Holiday and 
State ARRL Convention will he held 
Saturday and Sunday, August 2 and 3 
in Oklahoma City OK. In addition to 
the largest flea market in the South- 
w^t, the program will ioclude special 
programs, technical seminars, equip- 
ment displays, MARS meetings and 
unfque activities for the XYL For 
information and advance registration 
write Oklahoma Ham Holiday, P;0, 
Box 20567, Oklahoma City OK 
73120. 

UPPER ST CLAIR PA 
AUG 3 

The 38th Annual Hamfest of the 
South Hills Brass Pounders and Modu- 
lators will be held on August 3rd, 
from noon till dusk, at St, Clair 
Beach, Upper St. Clair Township, 5 
miles south of Mt. Lebanon on route 
19. Swap and shop, picnic space and 
swimming for the family. Mobile 
check in on 29.0* 52 simplex and 
popular 2 meter frequencies. Informa* 
tion and p re-registration at SI .50 per 
ticket {S2 at door) from Fred 
Schneiber, 181 County Line Road, 
Bridgeviile PA 15017. 

ANGOLA liSI 
AUG 3 

The original FM Hamfest will be 
August 3, 1975, near Angola, Indiana. 
Free flea market, picnic grounds, 
swimming, boating avaitabfe. Talk- in 
on 146.1&76, 14a94. For informa 
tion contact Fort Wayne Repeater 
Associationv Box 6022, Fort Wayne 
IN 46806. 

CANTON OH 
AUG 3 

Hall of Fame Hamfest and Auction 
rafn or shine, Aug 3, 1975, Canton, 
Ohio* Come to Canton for football's 
greatest weekend Saturday's actfvities 

— parade, enshrinement, NFL game 
Cincinnati vs Washington, Sunday — 
hamfest and auction at Stark County 
Fairgrounds* Main prizes— ICOM 230 

- Hallicrafters FPM 300 - Standard 2 



mtr hand held. For more info write 
WA8SHP, 73 Nimishillan St., Sandy- 
ville OH 44671 or call W8SWB at 
(216) 455-4449. 

LEVELLANDTX 
AUG 3 

The Tenth Annual Northwest Texas 
Emergency Net Swapfest and Picnic 
will be held in the City Park at 
Levelland, Texas on Sunday, August 
3, 1975. Bring your own picnic 
basket. Free registration begins at 
0900, Lunch at 1300. Swapping all 
day. This event is for the entire 
family. Mobile talk-in is the net fre- 
quency of 3950 kHz and via the 
Levelland Repeater CWR5AFX), on 
28-88. 

MONTREAL 
AUG 3 

The Montreal Hamfest will be held 
Saturday, August 3, 1975, 9 am to 5 
pm, MacDonald College Farm, Ste. 
Anne de Bellevue, PQ, on the west 
end of Montreal Island, Exit 26 off 
the Trans-Canada Highway. Admission 
$2.50 includes prizes, fieamarket, tech 
sessions, exhibits, mobile clinic (2 m) 
and an I nternatianal Tug-o-War, Activ- 
ities for XYL and kids. Talk-in 
VE2RM (146.40) 147.00, VE2PY 
146.88 (English), VE2XW 146,70, 
VE2DN 146J6 (French), VE2BG 
147.06, 146,52 simplex (both). For 
more info write Montreal Hamfest c/o 
VE2RM Inc., P.O. Box 201, Pointe 
Claire-Dorvat, PQ. 

WASHINGTON MO 
AUG 3 

The Zero- Beaters ARC will hold 
their annual hamfest on Sunday, 

August 3rd, at the Washington, 
Missouri city park. Free parking, auc- 
tion, and bingo for the XYLs, No 
admission fee or fee for parking in the 
traders row. Many prizes including 
rC'22A, station accessories, books and 
a handmade quilt. For info or tickets 
contact Kevin Weiskopf WB0MNP, or 
Zero- Beaters ARC, WA0FYA, Box 24, 
Dutzow MO 63342. 

RENO NV 
AUG 9 

Nevada Amateur Radio Association 
will host the annual "Sierra" Hamfest, 
August 9th, at the California Building, 
(diewild Park, Reno, Nevada. Pre- 
registration, SI 0. For information, 
contact NARA, P.O. Box 2534. Reno, 
Nevada. 

FLOURTOWNPA 
AUG 10 

The Mt. Airy VHF Radio Club {The 
Pack Rats) will hold their 19th 



Annual Family Day & Picnic on 
Sunday, August 10, 1975 (rain date 
August 17th) at the Fort Washington 
State Park, Flourtown PA. The Dela- 
ware Valley chapter of QCWA will 
again join us in the festivities. Alt 
hams and their families are cordially 
invited. Games and entertainment, 
free prizes to the kiddies, free soda 
Talk-in on 52,525 MHz FM - 146.52 
MHz FM - 222.98^224.58 MHz FM 
repeater. Registration S2 per family. 

WILLOW SPRINGS I L 
AUG 10 
The 41st Hamfest and Picnic will be 
held Sunday, August 10, 1975, Santa 
Fe Park, 91st and Wolf Road, Willow 
Springs, Illinois, Southwest of 
Chicago. Exhibits for OMs and XYLs, 
famous swappers row. Information 
con^ct John Raiger K9DRS, 8919 
West Golfview Drive, Ortand Park, 
Illinois 60462. Tickets write Joseph 
Poradyta WA9IWU, 5701 South Cali- 
fornia, Chicago I L 60629. 

HtLLIARDOH 
AUG 10 

The Central Ohio Radio Club, Inc*, 
will spor^or a Flea Market Hamfest 
Auction to be held Sunday, August 
10, 1975 from 8 am to 6 pm rain or 
shine at the Franklin County Fair- 
grounds, Hilliard, Ohio {just west of 
Columbus). Flea market, free auction, 
main prizes: Midland 30 Watt 2 mtr 
FM Mobile unit. Model 13-505, 12 
ch.. Regency 2 Watt 2 mtr FM hand 
held unit- Door prizes, XYL prizes, 
refreshments. Entrance and registra- 
tion — one (1) ticket @ S2/person 
(incfuding all prize drawings). For 
more info write CORC, Inc, P.O. Box 
23, Delaware OH 43015. 

NEWBURGH NY 
AUG 16 

Mt. Beacon A.R.C. 3rd Annual 
Hamfest, Saturday, August 16, 1975, 
8 am to 6 pm at Stewart Airport, 
Newburgh, New York. Inside Hangar 

E. Flea market and auction, door 
prizes, free parking. Rain or shine* 
Talk-in on WR2ABB 37/97, 94 and 
52. Admission: $1.00, tailgating $1, 
under 12 admitted free. For advance 
tickets write: Marty Irons WB2TBI, 
46 Magic Circle Drive, Goshen, New 
York 10924. 

M1DDLEFIELD MA 
AUG 1617 

Many activities are planned for 
both days of the NOB ARC Hamfest, 
August 16-17, at the MIddlefietd Fair- 



156 



73 MAGAZINE 



grounds, Middlefield MA. Talk-in on 
31/91, 43/03, 52 simplex, 34/94, 
52,525 and 223,50. Admission 
$3.0D/adult or $5/f amity. Flea market 
parking Si/car. For further info, con- 
tact Don Huntington WAIIQJ, 11 
Sutlivan Dn, Granby CT 06035. 

DECATUR AL 
AUG 17 

The Decatur Amateur Radio Club 
will host the North Alabama Hamfest 
in Decatur, Alabama on Sunday, 
August 17, 1975. Location is the 
campus of Calhoun Junior College at 
the Decatur-Athens Municipal Air- 
port. Doors will open at 8 am. Tickets 
$1,00 each will be available at door or 
in advance from Ken Hrxon WB4NLN, 
P.O. Box 9, Decatur AL 35601, Talk- 
in on 34-94 and 3.965 MHz. 

SAUK RAPIDS MN 
AUG 17 

The St. Cloud Area Hamfest will be 
held on August 17, 1975, at the Sauk 
Rapids Municipal Park from 1000, 
with registration and eyeball QSO, 
Swapfest $1.00 per call, refreshments 
and door prizes. For info contact 
WA0OTO. 

AURORA IL 
AUG 17 

The F.R.R.L, Hamfest will be held 
August 17th at Phillips 'Park, U.S. Rt 
No. 30, East of Aurora, Illinois. 
Picnic, 200 and family fun. Advance 
donation $1, $1.50 at park. SASE to 
P.O. Box 443, Aurora I L 60507. Two 
grand prizes and many others. 

YANKEE LAKE OH 
AUG 17 

The Warren Hamfest will be held 
Sunday, August 17, Yankee Lake, 
Ohio, on Rt, 7 five miles north of [80. 
Dealers' displays. Swimming and pic- 
nicing. Giant flea market (Vendor's 
fee: SI plus reg.) A $3 reg includes: 
Door prize, main prize and XYL 
tickets. More info: Hamfest, PO Box 
809, Warren OH 44482, 



BRANCHVILLENJ 
AUG 23-24 

The 550 Club - Oakland Repeater 
Association will holds its Family 
Piknik on August 23 and 24 at the 
Harmony Ridge Campgrounds, 
Mattison Road, Branchville, New 
Jersey. Flea market, Door prize 
TR22C, bring your own food, beer 
and soda provided* Hidden transmitter 
hunts (bring your handy talkie), 
hiking, contests. Talk-in 
147,49 146,49 repeat 10-70 & 52, 
Camping fee $4 per day, $5 per day 
w/ water and electric hook-ups. En- 
trance fee S2 per adult — S.50 per 
child under 12. Checks payable to 550 
Cfub — mail to: Rfck Anderson 
WB2Q0Q, 53 Gerstde Avenue, Wayne, 
New Jersey 07470, 

BELVIDERE (L 
AUG 24 

The Bel Rock Hamfest will beheld 
August 24th in BelvTdere, rilinois, 
Advance registration is SI. 50. For 
niore information contact: Bel Rock 
Hamfest, P.O. Box 1744, Rockford IL 
61110. 

MARSHALLTOWN lA 
AUG 24 

The Iowa 75 Meter picnic will be 
held August 24 at Rivervrew Park in 
Marshatltown, Iowa. Bring your own 
table sen/ice and a dish for the pot 
luck meal; coffee and soft drinks are 
furnished. No registration fee. For 
more info contact Iowa 75 Meter Net, 
Mary Keener WA0DAG, R,R. 2, 
Cascade I A 52033, 

SPRINGFIELD MO 
AUG 24 

The Southwest Missouri Amateur 
Radio Club will hold its annual Ham- 
fest, swap meet, and family picnic on 
August 24, 1975, at Lake Springfield 
Park, Our highly successful meeting 
draws over two hundred radio ama 
teurs and their fa^nifies each year 
Please send any merchandise for prizes 



or enquiries to me at the following 
address: Joe Hargis WB0CIW, Secre- 
tary, Southwest Missouri Amateur 
Radio Club, 3228 N. Wildan, Spring^ 
field MO 65803. 

LAPORTE IN 

AUG 24 

The LaPorte County Amateur Ham- 
fest will be held 24 August, 1975, at 
the County Fairgrounds in LaPorte, 
Indiana, 60 miles East of Chicago. 
Paved Midway for sellers, inside tables 
available. On-site camping with hook- 
ups; Advance tickets are $1 each, 
$1.50 at gate. Cold drinks and food 
available. Contact Dave Nicolaus 
WB9A0U, RR7, Box 275, Valparaiso 
IN 46383. 

SAN FRANCISCO CA 

AUG 29^SEPT 1 

The Quarterly NO RCA L DXers 
(Northern California DXers} gabfest 
win be held Labor Day weekend at 
the El Rancho Inn, 1100 El Camino 
Real, Millbrae CA 94030. $1 reg. at 
door, Emphasis on SWL DXing. Tech- 
nical sessions, displays, quiz, auction 
and free refreshments. Door prizes. 
For more info write NORCAL, Rick 
Heald, 17412 Rolando Avenue, Castro 
Valley CA 94546, 

MONCTON NEW BRUNSWICK 
AUG 29-SEPT 1 

The Moncton Ares Amateur Radio 
Club will sponsor the Atlantic Canada 
ARRL Amateur Radio Convention, 
August 29 - Septefnber 1, 1975 at 
the Hotel Beausejour, Moncton, New 
Brunswick, Exhibits, technical forums 
conducted by ARRL Headquarters 
personnel, VHF forum, swap shop^ 
buffet Saturday night followed by 
dance, dinner and entertainment 
Sunday night, hidden transmitter 

hunt, etc. Tatk-fn on 146.28 - 88 and 
146,52 simplex- For full information, 

write: Moncton Area Amateur Radio 

Club, P.O. Box 115, Moncton, N.B. 



DIGITAL FREQUENCY COUNTER 



50 Hz to over 250 M Hz - 8 digit LED display 
less than 90 nnV to 45 MHz — less than 250 mV 
to 250 MHz — packaged 10 IVlHz clock — ± 1 
PPM stability — AC or DC operation — wired 



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edi 



CALL OR WRIJ'E FOR DETAILS 

AND PRICES 

Efectronic Development, inc., P.O, 

Box 951, Salem, Oregon 97308 (503) 
399-9660. . 




V 




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is always looking for photos or art- 
work suitable for cover use - and the 
pay is good. 



18" FACSIMILE RECORDERS 

FOR SALE 

The teading manufacturer oi IB"' facsimtle weather 
chart recorders is now updating an exacting n^etwork to 
solTd state equipment. This updating is making available a 
nurnber of 18" weather map fecorders ideally suited for 
anyone interested in experimenting with facsimile. 

These recorders, with stiitabJe receiver and FSK 
converter, can be us^d to monitor radio weather chart 
broadcasts as well as press vyire photo transmissions. With 
some modifications, data from weather satellites can siso 
be received* 

These recorders are reasonably priced and available on 
a first come, first served basis. 

Calf or write Mr. Armand D. Bouchard: 

ALDEN ELECTRONICS & IMPULSE 

RECORDING EOUIPMENT CO., INC. 

Washington Street, Westboro MA 01581 

617/366-8851 



■»^ 






AUGUST 1975 



157 







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three styles 

QSO info back 
two colors 

LOW PRICES 



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Style W - Stack typfi, blue wortd 
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These QSLs are printed on Fine Quality Coated Card Stock and ar« as good or btttter than cards 
sold elsewhere for several times the price. We can offer this fantastic lovw price, because we "gang 
print" orderE betvyeen other jobs in our own print shop which keeps the costs way down and we 
pass the savings on to you. If you haven't been QSLing as much as you'd like to because of the cost 
of cardK, dq yqu feally have an excuse anymore? Get some cards and help improve the image of 
U.S. Amateurs. Please ajfow 6-8 vveeks for delivery. 









ONLY. SOD 



X 

Ham radio is too great a hobby for us to 
keep it to ourselves. Let's tell the whole 
world about rtl And what better way 
than by sporting this attractive lime- 
green bumpw sticker on your caw\ tt's 
only 5CM — and tt's phosphorescent so 
you can see it even at night. Go 
ahead . . . SPREAD THE WORD! Order 
yours TODAY! 



SOLID STATE 
PROJECTS 

S4 
More than 60 projects of 
interest to anyone in elec- 
tro nJcs. The devices range from 
a simpte transistor tester to a 
ham TV receiver. This collection 
will help you become more inti- 
mately acquainted with ^eners. 
iCs and varactors, etc* 





2W FM HANDBOOK 

hardbound $7 
soft bound $5 

Contains almost every con- 
ceivable circuit that might be 
needed for use with a repeater. 
All circuits explained in detail. 
All aspects covered^ from the 
operator to the antenna^ 




TWs i-|ifet4i.FM Hartdlifl*!' 



VHP PROJECTS FOR 
AMATEUR AND 
EXPERIMENTER 

$4 
A must for the VHF op. 
Opening chapters on operating 
practices and getting started in 
VHF, both AM and FM, 
faflowed by 58 chapters on 
buitdmg useful test equipment^ 
modifying existing and surplus 
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iiii^m/ttuAKu^iit j^imJ. 


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..1 


JM^Sj^^^M ''■•■ '■■■■ • ^^ 








1^ 






v 



LATEST RELEASES froin73 publications 



RF and DIGITAL 

TEST EQUIPMENT 

YOU CAN BUILD 

RF burst, function, 
square wave gener- 
ators, variable length 
pulse generators — 
100 kHz marker, if 
and rf sweep gener- 
ators, audio osc, af/rf signs! injector, 146 
MHz synthesizer, digital readouts for 
counters, several counters, prescaJer, micro- 
wavemeter, etc. 252 pages. $5.95 






ifeS'.- ■■:■*>:'. -'V; 



PRACTICAL 
TEST 

INSTRUMENTS 
YOU CAN BUILD 



37 simple test 
instruments you can 
make — covers VOMs, - ^ I 

VTVMs, semicon- ^ 

doctor testing units, 
dip meters, watt 
meters, and just about anything else you 
might need around the test lab and ham 
shack. S4.95 








4 STUDY GUIDES 
NOVICE - $4 
ADVANtlED- $4 



GENERAL— $6 
EXTRA — $5 



FCC exams got you scared? Frustrated hy 
theory fundamentals? There's no r»eed to 
worry. 73^5 four License Study Guides will hetp 
you breeze through any of the four touc^h 
eKarr^! They are the ONLY guides which cover 
ALL the material you will have to know« Many 
amateurs find that one quick reading through 
our guides is enough to get thern through with 
no sweat. 



^4« 




DIGITAL CONTROL 

OF REPEATERS 

softbound $S hardbound $7 

Here's a book for the 
FMer who want$ to cf^ign 
and build a digital repeater 
control system. Contains 
sections on repeaters, basic 
logic functions, logic 
circuit d«stgn, control 
systems, support circuits, 
mobile InstalldtionSf 
touch -tone^ plus a special 
section on a "mini" 
repeater control system. 



COAX HANDBOOK 

$3 

All about coaxial 
cables, connectors and 
applications. It's all hefe — 
pictures, part numbers and 
specifications for all types. 
Includes lengths for 
different types for quarter, 
half and full wave feed- 
line^. 



73 BINDERS 

SS 
These binders are a gorgeous red ar»d come 
with the nicest set of year stickers youVe ever 
$een. The perfect thir>g for 'storing your issues 
of 73 so that they won't get lost or spift on, or 
into the hands of the Jr. Op. Dress up your 
shack with these binders. 



maM 



158 



73 MAGAZINE 




Startling 
Learning 
Breaicthrough 




NOVrCE THEORY TAPES 
Set of 4 Tapes only SI 3,95 



You'll be astoundeci ai how r«slly simple 
xh0 thtory ts wrfien you hear U explained on 
The^ tapes. Three tapes of theory dnd one of 
quettioris and answers from the letest Novice 
ex$rm give you the edge you need to bwezQ 
through your ex^m, 

73 is Interested in helping get mone ama- 
tfiyrs, so weVe giulfig you the complete set of 
four tapes for Ehe incrediblv low price of 
ONLY S1 3.95. 

Scientists have proven that yoii learn, faste^r 
by lisferiing then by reading bucause you can 
play s cjB&ette tape over and over in your spa^ 
lime — oven while you're driving J You get more 
and more info each time you hear it. 

Yq<i can't progrras without so4id fund^ 
mental^- These four houNongi tapes give you all 
the b^cs you'll need to pass ihe Novice exam 
eatlty. You'll have an understanding of the 
bastes which wiiF be ir^ valuable to yoy for the 
rest of your life^ Can you afford to take your 
Novice exam without fir^i listening to your 
tapes? 

^ / 



1975 fm 
repeater atlas 




LISTINGS 

BY 

STATE 

ORDER 
TODAY! 



STtLLONLYSl-50 

73's ali new RKPEATtR ATLAS is a must for 
every ham on 2 mctcn. Thccc are 2,500 
Kpejtcn around the world 12,000 of tliem in 
the U.S.). and thi^ itias lists Ihem ali! Just o(T 

the presses, the [97$ edition b the inost 
up-to-dite llstifig you i;3j\ buy. And monthly 
rvpcAter updates m th« 73 newspages makes 
Hurc that it slays Ihdt way* You can still 
purchase this inviiluablc tool for JUST $LSO. 
Isn't It nice lo know that there are a few pUccs 
left where your dollar Is still worth iomet King? 






Noiv you can learn the code in a fraction of the time it 
used to take! 

Ih mm Uu I I 1 1 I ^ ^^^Y^ on ^f^V cassette player so you can 
I V ^H T W \m %^ li^ ^H practice anywhere afiytimel 




SYSTEM 



■^ S WPM This m ihe beginning tape for 
p«ople who do rvot know ihe cod« at alK k takss 
Them through the 26 lett«r^. 10 ntunbers »nd 
necfi^tsarv punctuation^ complete wiih practice 
■vvry ste^ Of ttm wey uttng the newest blitz 
teaching techniques. It it alfiiosT miraculous! In 
One houf many peopEe — including kids of ten -^ 
MS ibNr 10 msster the code. The ease of learning 
ghm confidence to beginners who might otherwue 
difop out 

D 14 WPM Code groups dgatn, at a brisk 14 
per wo yoM w\U be at ease when you ut down in 
front of the steely eyed government inipectorand 
he starts sanding you plain languagfl at only 13 per. 
You need this entra mergin to ovurcome the panic 
which Is universal in the toil situations. When 
you've iper^t your money and time io take the test 
yoy 'II ihank hea>vens you had this back breaking 



O 6 VVPM This ii the practice tape for the 
Novice and Technician licennt. It h made up of 
or^ $olid hour of code> sent at the official FCC 
standard (no Other tape we've heard u$e« the$e 
fi^nd«rd$, $0 many people flunk the code when 
they ere fudderWy - under pressure — faced wuh 
cherecter$ sent ai 13 wpm and placed for 5 wpm). 
This lape ti not cnemofuible, unlrke The ieny 6 
wpm t9|>e, since ih« ccm^ ^oup^ are ^ntirelv 
rarvdom characters sent in groups of fwe, Praciice 
ihif one duiing lunch^ white in the caf« BnywheriB 
and you'll be r?iorB then pripered for the e^ FCu 
exam 

21 WPM Code If wvhdi gets yOii wtren you 
go for the Extra Class license, li is lo embarrssstng 
to panic out just becauie you didn't prepare 
yourtetf with this tape. Though this is onty one 
word fester, the code groups are so difficult that 
you'll almost fa^ asleep copying the FCC stuff by 
cornparison. Users report thai they can't believe 
how iisy 2Q per really ii with this fantasiic one 
hour tape. No one who can copy these iape( can 
possibly fail the FCC lestn Remove all fear of ihe 
codfe' forever with these tapes. 






in 




Latest FCC News 

{from inside the FCC) 
Latest Docket Releases 

usually In entirety 
Late DXpedition News 
Hot Propagation Report 
Job Openings 
Contest News 
Conventions — Hamfests 
Brand New Products 
Inside Industry News 

The fact i$, if you are an a<^tute shopper, 
you can pay 50% more for Br^nd X than the 
subscription price of Hptline (a mere $8 per 
year by First Class MaiU and end up with a 
newsletter which ii about half as btg (half as 
much news). 

Hotline overcomes the two month news 
de^ey of 73 Magazine (and ell other ham 
magazines) bv bringing you the latest hot 
news while it it ttilt news. This pu& you in 
the know on tt»e air — over the repeater — 
ar>dat your ham club. 




^'9 if^le Bom. 



Spseue 



.4^5% 



O^rTOiX' tMf^ WTA&Af\' 



t 



^ 4^1 Mm 



Kr* ib'iriiiHi ui- 2^\r<in:'. 



*^ 



i«««i 



AUGUST 1975 



159 




Wt^- Akent- oBniMt - ^^ at it tim u/aif - 




So Iwuf nmek cbm tkB setmid q^e^ emtP - K/otkimq, /ualfyf 



12 REASONS FOR SUBSCRIBING TO 73 MAGAZINE, 



RIGHT NOW. 



You get every issue — makes a first rate electronics reference library 

No more missing issues sold out at the newsstand 

Many more articles every month than other ham magazines 

The most and the best of the ham advertising — see new products first in 73 

The editorials — like 'em or hate 'em — they do make you think 

Complete FCC releases in detail so you won't miss anything important 

The newest state of the art construction projects by top authors 

Plus five other reasons which are too obvious to mention here 




il TODAY to : 

magazine 

Peterborough, New Hampshire 03458 



Call 



Address 



i_ 

I Qilil 

I 
I 



State 



Zip 



n 



Fiustsr charge 



n 




□ Check 



Card No. 



I Signature 

I 
I 



Expiration Date 



Total enclosed 



tn Novice Theory Tapes 

o 5 WPM Beginners Cassette 

n 6 WPM Back Bfeaker Cassette 

D 10 WPM Canadian Code Tape 

o 13 WPM Genera! Practice Tape 

P 20 WPM Extra*Back Breaker Tape 

D 5-6- 1 3-20 Tape Package 

E3 Vintage Back Issues 

o Recent Back Issues 

a Very Becent Back Issues 

P Hotline - 1 year 

^ 1975 Repeater Atlas 

-I250QSL - Style 

niBOOQSL- Style 

!i 1000QSL- Style 

a 2000 QSL - Style 

n Bumper Stickers 

E) Novice Study Guide 

tJ General/Tech Guide 
^' Advanced Guide 
^ Extra Guide 
uSotid State Proi 
c VHF Projecti 
(i'2m FM Handbook 
t SSTV Handbook 
- Digital Control 



SI 3.95 
4.95 

4.95 

4.95 

4.95 

4.95 

T4:95 

5.00 

5.00 

EDO 

8.00 

1.50 

a Y 6.00 

DY 10,00 

D Y 1 5.00 

□ Y 20.00 

@ 50c each 

4.00 

6.00 

4.00 

5.00 

4.00 

5.00 

DHard S7 DSoft 5.00 

DHard S7 DSoft 5,00 

DHard S7 DSoft 5.00 



■^ 



ilHftf 
DW 
DW 
DW 



□X 

DX 
DX 
DX 



I 



I 
I 



J 



160 



73 MAGAZINE 




45 



Q 



Q 




A/ V^ hi 



^°^-^c 



-^^^a 






^^;> 



^if<^< 



/ar^-^ 



ROHN manufactures 
towers that are designed and 
engineered to do specific jobs 
and that is why we have the FOLD- 
OVER TOWER . . . designed for the amateur. 
When you need to "get at" your antenna just turn, 
the handle and there it is. Like other ROHN big 
communication towers, they're hot dip galvanized 
after fabrication to provide a maintenance free, 
long lived and attractive installation. ROHN towers 
are known and used throughout the world ... for 
almost a quarter century ... in most every type of 
operation. You'll be in good company. Why not 
check with your distributor today? 




ROHN 



iWANUFACTURING 



® 



OfViSION Of 



P.O. Box 2000/ Peoria. II!. 61601 




"V^-^^ 

^^X^* 



°^^/''r 




AUGUST 1975 



161 




5k 67 + channels 
^ Simplex — Duplex 

^ Modular construction 
^ Super hot receiver 



3|c ^ 5 kHz freq. deviation 
jjc MOSFET front end 
)^ 5 helical filters 
^jc 10 Watts output 



This is the radio everyone has been talking about. The IC-230 was the first Phase 
Locked Loop transceiver to be introduced to the U.S. amateurs and it is still the 
best unit available for your car. The IC-230 comes with all the standard 30 kHz 
channels installed and operating in the unique double mixed phase locked loop 
synthesizer that puts out one of the cleanest signals available anywhere. FIVE 
helicalized resonators in the rf section and three i-f filters help make it almost 
impervious to intermodulation. Because of the amazing versatility of the PLL 
system used in the 230, 15 kHz spacing channels may be added by simply 
plugging in four inexpensive crystals. The IC-230 modular construction makes 
repairs simpler and faster when and if they are needed. 

See your (COM A UTHORIZED DBA LER TODA Y! 



BEILAIRE ELECTRONIC 



supply 



5200 BELLAIRE BL VD. 
BELLAIRE, TEXAS 77401 
Phone: 713-667-4294 



162 



73 MAGAZINE 



42.95 

Kit: includes; 
Power Supply, 
Display card. 
Timing card, 
Misc. parts, less 

C3S6a 



ST ^.9 



Pd«li 



•• 






Off 



ftitn 



DIGITAL 

READOUT 

TUNING 



WORKS WITH ANY 160-20 METER TRANSMITTER OR 
TRANSCEIVER WITH JUST A PICKUP LOOP 



All IC 

Build it Into your rig 
Converts to 15 and 10 
Even works with QRP rigs 
Mobile too 



• MHz/KHz coarse/fine readout 

• Frequency to 100 Hz -*- 

• Easy to build 

• Power suppfy included 

• Crystal controlled time base 



BRING YOUR RIG TO THE STATE O FTHE ART 



HURRY, I don't want to lay out several hundred bucks for a new rig^ 
but 1 gotta have digital readout (doesn't everyone?) 



Here's a check for. 



for. 



.unitls). You pay shipping. 



Name. 



Call. 



Address. 



State 



P.O. Box 357, Provo, Utah 84601 



AUGUST 1975 



163 




digital ciocic 



qf? 



•V2" LED Digital Display 
•AM PM Indicator 
•Povwr Failure Indicator 

•Power- Lock feature allows clock to hold correct 
time in case of brief power failures 
•Size H 3 1/8 X D 3 3/8 X W 3 3/4 inches 

• Color — White only 

• 110 volt 60 Hz 

•THIS IS NOT A KITI 
$29.95 in Continental USA 



liquid 
crystal 

display 

watch 



y 



•,**». 



. . . You never IhouglU it could 
happen but it did, and you saw it 
first in 73. The digital timepiece for 
your wrist is finally available at the 
price of an ordinary wind-up watch. 
Yet this QUARTZ LIQUID 
CRYSTAL wiitch is the equal of 
those yoirve seen at two and three 
times our LOW PRRH. 



•Pulsating dots show elapse of seconds 

•Continuous Display 

• Mfd. by American Micro Systems International (AMI) 

•Guaranteed for one year by manufacturer 

•Specify stainless or gold color 

•Color coordinated leather watch band 

•Crystals will not fade in sun like other liquid crystals 

•PP in continental USA 

•THIS IS NOT A KITI $55.00 



491 Quad segment driver for LED displays 

492 hex digit driver for LED displays 

1 for $1.00 10 for $7.50 



7446 IC BCD to seven segment for common anode 

displays 

1 for ST. 00 10 for $7.50 



14 pin Chip Clip used for troubleshooting IC 
1forS3.75 10forS35.00 



P2102 
1101 
MCI 550 
TC430 



1024x1 RAM 

256 X 1 RAM 

rf op amp 
quad re tone gen 



10 

S55.00 
12.50 
10.00 
30.00 



GE elapsed time meter 2 5/8" x 2 5/8" sq by 3" 
long 120 V 60 Hz GE cat. no. 50-236402AAAA 2 
jap 

S7.50 



Computer logic diodes IN4148, same as IN914 

tested prime units on tape 

min 25 for SI. 00 100forS3.00 



11 i| 17 u 1^ 



I* 



resistor and cap array all re 
sistors are 50n caps are .01 

1 for $1.00 

10 for $6. 50 



1 00,000 uF cap. at lOv 
1 forS2.75 10 for $20.00 



Push button switch spst normal open 
4 for $1.00 



25 for $5.00 



We are a surplus housc\ All hems are new unless orhenxffse staled and all are 
!007f guaranteed^ IJ yon liove surplus send list f^r sample. All safnples are 
accounted f(H\ 

Florida residents remit 4% state sales tax. 
All items FP in continenial USA. 

Marlin P. Jones & Associates 

P.O. Box 9023 • Riviera Beach • Florida 33404 



164 



73 MAGAZINE 



THE FIRST AND STILL 
THE 

the exciting super 



compact 



icoM] 230 



PUT OVER 67 CHANNELS IN THE PALMS OF YOUR HANDS 

SPECIAL FEATURES: 

No More Crystals . . . Over 67 ... fully synthesized channels available. 

All Channel Capability , . , Travel with confidence that you'll be able to work 
all repeaters along the way. 

Super Compact . , , 2.28" high x 6,14" wide x 9,72" deep at a weight of only 
5,5 lbs. 

Quick Dismount Mobile Mount . . . Allows quick car installation. 

Easy Operation . , • Punch up frequency, select repeater or simplex mode, and 
you're on the air, (A crystal may be added for a unique repeater frequency,) 

Modular Construction . , . In case of a problem, modules can easily be removed 
and sent for repair, A replacement module will be air mailed to minimize 
down time. 

Super Hot Receiver ... Better than .4uv / 20db, sensitivity, helical filters to 
eliminate intermod , . , plus a super E filter and a mosfet front end. 

IF THERE IS A SIGNAL, YOU'LL HEAR IT ON THE IC230! 



enterprises 

866 RIDGE ROAD, LANSING, N. Y. 14882 



AUGUST 1975 



167 



Vanguard 

now has the 

World's Largest Selection 

of Frequency Synthesizers 

from $ 129*95 



f: 



W(3ff3®(Bia&JS> 



14 6 .9 



FREQUENCV SVMTHE^tzeR 



Smallest size of any commerciatlv available 
synthesizer - only 1-3/8" x 3-3/4" x 7". 
Excellent spectral purity since no mixers are 
used. 

.0005% (5 parts per million) accuracy over 
the temperature range 
of -10 to +60 a 
Immune from supply 
line voltage fluctuations 
when operated from 1 1 
to 16 volts dc. 
Up to 8000 Chan nets ! 
available from one unit. 
Frequency selected 
with th u m bwheel 
switches. 

Available from 5 MHz 
to 169.995 MHz with 
up to 40 MHz tuning 
range and a choice of 1, 5 or 10 kHz 
increments (subject to certain restrictions 
depending on the frequency band selected). 
Top quality components used throughout 
and all ICs mounted in sockets for easy 
servicing. 

All synthesizers are supplied with connect- 
ing hardware and impedance converters or 
buffers that plug into your crystal socket. 



Vanguard frequency synthesizers are custom 
programmed to your requirements in 1 day 
from stock units starting as low as $129.95 for 
transmit synthesizers and $139.95 for receive 
synthesizers. Add $20.00 for any synthesizer 

for 5 kHz steps instead of 
10 kHz steps and add 
$10.00 for any tuning 
range over 10 MHz. Max- 
imum tuning range avail- 
able is 40 MHz but cannot 
be programmed over 
159.995 MHz on transmit 
or 1 69,995 MHz on receive 
(except on special orders) 
unless the i-f is greater than 
10.7 MHz and uses low 
side injection. Tuning 
range in all cases must be 
in decades starting with (i.e. ~ 140,000 — 
149.995 etc J- The output frequency can be 
matched to any crystal formula. Just give us the 
crystal formula (available from your instruction 
manual) and we'll do the rest* We may require a 
deposit for odd-ball formulas. On pick-up or- 
ders please call first so we can have your unit 
ready. Call 212-468-2720 between 9 am and 4 
pm Monday through Friday. 



SEND NO MONEY. 

WESHIPC.O.D. 

ORDER BY PHONE 

AND SAVE TIME. 



i 

Available for aircraft, fire, police and amateur frequencies. 

We ship open account only to U.S. and Canadian government agencies, 

universities and selected AAA rated corporations. 

VAT^GUAUD I.ABS 

196-23 Jamaica Ave., Hollis, New York 1 1423 



168 



73 MAGAZINE 



I 



MEET THE STATE OF THE ART 

ON 2 METERS... 

THE ITC MULTI-2000 
CW/SSB/FM TRANSCEIVER 




band. Fully solid-state and em- 
ploying modular construction, 
the MULTI-2000 enjoys features 
found in no other 2m transceiver. 



Whether your interest is sim- 
plex, repeater, DX or OSCAR the 
new ITC MULTI-20G0 lets you get 
into all the action on alf of the 

FEATURES 

• PLL synthesizer covers 144-148 MHz in 10 kHz steps 

• Separate VXO and RIT for full between-channei tuning 

• Simplex or ± 600 kHz offset for repeater operation 

• Three selectable priority channels 

• Multi-mode operation (CW/SSB/NBFM/WBFM) 

• Built-in AC and DC power supplies, noise-blanker 
squelch and rf gain control 

• Selectable 1W or 10W output 

• Separate S-/power and frequency deviation meters 

• Built-in test (call) tone and touch-tone provision 

• Excellent sensitivity (.3xiV for 12 dB SINAD) 

• Superior immunity to crossmodulation and 
intermodulation 

ntroductory price: $695. 





Inc 



8400 N. Pioneer Parkway, Peoria IL 61614, Phone 309-691-4840 
Cliff Morris W9GA0 - Jim Placli WB9BGS 



A I l/M t 



imc 



169 



WRITE FOR 
PRICE QUOTES 




HAMTRONICS 



IC 230 

• PL L SYNTHESIZER 

• 67 CHANNELS - 30 KH SEPARA- 
TION 

• HELiCAL FILTERS 

• AUTOMATIC PROTECTION CIR- 
CUITRY 

• MODULAR CONSTRUCTION 



■■^^<,i.'< S.-f/iiy^ 



■^m^^^<v-K^, 




IC21A 

• 24 CHANNEL CAPABILITY 

• 7 CHANNELS SUPPLIED 

• MOSFET FRONT END 

• 0.4 UV SENSITIVITY 

• 5 HELICAL FILTERS 

• BUILT IN AC & DC 
SUPPLIES 

DV-21 



POWER 



• FULLY SYNTHESIZED VFO 

• OPERATES IN 5 OR 10KH STEPS 

• COVERS ENTIRE 2 METER BAND 

• SCANNING CAPABILITY 

• 2 PROGRAMMABLE MEMORIES 

• TOUCH KEYS TO SET XMIT & 
RECEIVE FREQUENCY 






AC* §.4^ 



V* 'rfJ 




IC22A 

• 22 CHANNEL 

• 5 CHANNELS SUPPLIED 
•SOLID STATE TR SWITCHING 

• 10W-1 W POWER SAVER OPTION 

• TRIMMER CAPS ON EACH 
CHANNEL 




ICOM 30A 

• 10 WATT OUTPUT 
•ALL SOLID STATE 

• 0.6 UV FOR 20dB QUIETING 

• 22 CHANNEL - 5 INSTALLED 

• MODULAR CONSTRUCTION 




master charge 



I 



I 




A DIVISION OF TREVOSE ELECTRONICS 4033 BROWNSVILLE ROAD. TREVOSE PA 19047 

215 357 1400 or 1475 



170 



73 MAGAZINE 



ICOM 




IICOMI 






^^tf^ 



O^r 










^'"t^^o So 



'"'"^c^,/*/^!© 



O/^ 



^0.96 



UMie QUAKTITY 

VARITRONIC'S 
AS-2HG 

5/8 2 METER 
GROUND PLANE 

3.5 ifb GAIN 




low in - 70 W out 




22 (FUNNEL 
2METER FM 

10 WAns 



ONL¥ $249.00 



ReADV TO 1 


94/94 


GOON^ 2 


34/94 


3 


22/62 


4 


£a/88 


5 


52/S2 



2 METER AMPLIFIERS 



$139.95 

2 MtO - 70 L 



THE CROwimi vm of scs ampufiers 

IKCIUDE THESE NO COMPROMISE FEATURES: 



Cdflip4et8lv Solid State BnMdfaWMl 0»%n Rn^ub-ei Ng Retunlng 
AcrtKs Band SiJietiMi Baakv^ f tif : 

Qmi C4*i#l POw> FM «t Psafc Efficitficy 

€tei A&Lin«r for ^B of Low Po#m FM 
Encreated T R Ptl^y for SSB/CW Oi»r»!iofi, Puiiy VSWH mmJ Ri 
Voliaiiv ProtoctAii Och Yht Wvnnty eft Entcfv Arnplifief . Under One 
DB I^HTtictn LcH$ in Rflotwtv 






TOUCH TOKE PAO 

SALE V29.9S 
VEGA BEEP BOX 

Extfifvdi ThTu Augufi . , - 12 Buttoft T»l Touch 
Self -Contained eatterv. AudiW# Coupled. Mo Wiring. 



c'*i^5l^o<' 






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"O,) 



•'O. 



•sr 



kss 



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1 WAn = 25 WAns OUTPUT 




S49.95 Kit 

S69,95 A»«nbr«d 

AN AMPUHER 
FOR YOUR HAND-HELD 

Carrier OpentBd Refty Can Be Driven From 
lEtOmA. No Tuning. Qutpui Shqct Circuit 
ProlvctKi^ Easy to IrtstaU & QperaM^ 



■^^\1 






^p 






1108 SO, 3rd STREET • LAS VEGAS, NEVADA 89101 
Call or Write: Norm, W71UC 702-382-4305 
OS^DER UNDER Si 00 ADD S2.S0 FOR SKIPPING ii HANDLING , . . NEVADA RESIDENTS ADD SALES TAX 



WE DON'T HAVE 
YOUR NUMBER 

BUT YOU HAVE OURS 

Toll Free 

(Cont. 48 States) 




(MO. cust call 314-993-6060 coll.) 

CALL 

RADIO CENTER 




ST. LOUIS 

FOR NEW AND USED 
AMATEUR RADIO EQUIPMENT 



IVe Trade on New or Used 
Charge it on Master-Charge or BankAmericard 

HAM RADIO CENTER INC. 

8342 Olive BL. 

P.O. Box 28271 

St. Louis, IVIO 63132 





start 

future 




mmm 



Midland's 220 MHz mobile transceiver puts you into this 
fast developing band for less than you might think. 10-watt 
output powen 12-channel capability with crystals for 223,5 
simplex, plus these professional performance features... 

A dual conversion receiver with complete multiple FET front end coupled 
with high-Q helical ized cavity resonators • Zener regulated, crystal con- 
trolled first and second oscillators • 10-watt output power transmitter (switch- 
able to 1 watt) with zener regulated crystal oscillator • High-Q and shielded 
stages for minimal interstage reaction • Encased low-pass filter • VSWR 
bridge and four DC amplifiers to monitor output and give instant automatic 
protection • Accessory jack for tone burst and discriminator filter • Swing-up 
circuit board for easy access to all sections,, .all modules easily removable 
• Operation on 13.8 volts DC, negative ground • Compact steel case 2V4" h. 
X SW wide x 8W d. Complete with mike, mounting bracket and hardware. 





asvP- 

posmv. prao«ca- s^PPOrt 
,o, your repeater ^^^^^^ 
:reXrmoSe tr'ansoe-.ver. 



Write for free Midland Amateur 

Radio Catalog , . . see vv/iy 

"COMMUNICATIONS IS OUR 

MIDDLE NAME" 



i IMXERtsJAXIOM Air 

Communications Division 

P.O. Box 19032 
Kansas City, Missouri 64141 



y^*"*^' 



MODEL 13-509 



%. - #; 



JCI-W^t*K» 



■■;■■• ■* ' 



•:*iS»^:. 



F 1*"^' 



3^.^^^^ii^fc>__rf^ 



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AUGUST 1975 



173 











The front panel and control locations have been changed to make 

the IC-22A even better looking and easier to operate. The new 

design allows the use of larger channel numbers which may be 

viewed from the left side or right side by reversing the window position and installing a new 

dial, (optional at nominal cost) 

Inside is the same high quality radio construction and engineering that has made the IC-22 the 
most reliable, most popular two meter crystal controlled set on the market. 
When you join 22 channels of capacity (five supplied) with the unexcelled performance of 
helical RF filtermg in the receiver front end then add solid state T-R switching you get one 
great radio for vour money. All the great features that made the IC-22 so desired are still 
there Including, 1 watt/10 watt switch option, trimmer capacitors on both receiver and 
transmitter crystals plus a 9 pin accessory jack with the discriminator already wired for 
frequency calrbration 




Smith Electronics 

1226 9th Ave. N., Fort Dodge, Iowa 50501 



174 



73 MAGAZrNE 



RGS 





0Q8A MICROCOMPUTER KIT 

8008 CPU, 1024 X 8 memory; memory is expancj- 

able. Kit includes manual with schematic, program- 
ming instructions and suggestions; alt ICs and parts 
supplied except cabinet, fuses & hardware. Includes 
px. board. $375.00 

MANUAL ON LY,S25.00 
|no discount on manual) 



S12.0Q VALUE FREE 

With each order of S50,00 or more, a FREE subscription 
to BYTE, the new computer hobbyists' magazine. ASK 
FOR IT when you order; we won't include it unless you 
ask. (Offer open to residents of continental U,S, onlyj 



008A-K ASCII keyboard input kit. 
008A-C Audio cassette adapter kit 



$135.00 
$100.00 



Details on computer, peripheral kits in our flyer 



THE CUBE" Fully assembled subaudibte tone 
generator for small handheld or portable FM radios* 
9*16 volts; no moving parts, set anywhere between 
98 & 240 Hz with a trim resistor. 
.5"x .6"x .8" $19,95 

Set on frequency by the factory, $5.00 extra 



TTL 








7400 


$ .20 


7485 


SI. 40 


7401 


.20 


7486 


.50 


7402 


.20 


7489 


2.90 


7403 


.20 


7490 


.80 


7404 


.25 


7492 


.80 


7405 


.25 


7493 


.80 


7406 


.46 


7495 


.90 


7407 


.45 


7496 


.85 


7408 


.25 


74107 


.50 


7409 


.25 


74121 


.60 


7410 


,20 


74122 


.60 


7411 


.30 


74123 


1.10 


7413 


.85 


74125 


,65 


7416 


.45 


74126 


.65 


7417 


.45 


74141 


1.25 


7420 


.20 


74150 


1.70 


7430 


.20 


74151 


1.00 


7432 


.30 


74153 


1,40 


7437 


.50 


74154 


1.70 


7438 


.50' 


74157 


1.40 


7440 


.20 


75161 


1.50 


7442 


1.10 


74161 


1.70 


7446 


1.45 


74164 


2.00 


7447 


1.45 


74165 


2.00 


7448 


1.45 


74166 


1.75 


7450 


.20 


74174 


2.20 


7451 


.20 


74175 


2.20 


7453 


.20 


74176 


1.60 


7454 


.20 


74177 


1.35 


7473 


.45 


74181 


3.90 


7474 


.45 


74192 


1.50 


7475 


.80 


74193 


1.45 


7476 


.50 


74195 


1.00 


7483 


1.10 







PS 25-- 1 to 25v la lab type power supply with adjustable current 
limiting; remote sensing & remote programming for voftage & current. 
Instructions included. All parts except chassis, meter(s), px, board. 
Kit of parts with schematics SI 4.95 

P.C. boards available. No. 007 S3,00 ea. 



SOME NEW TRANSISTORS . 


m m 




1-99 


100+ 


N1 TO-92 


NPN 


Darlington 




$ .35 


.30 


N2 TO-92 


NPN 


lo-noise. 


lo-leve 


1 


.15 


.10 


N3 TO-92 


NPN 


medium 


purpose 


.20 


.15 


N4 TO-92 


NPN 


2N3904 


type 




.15 


.10 


INJ5 TO-92 


NPN 


UHF 






.20 


.15 


N6 TO 92 


NPN 


RF-tF 






.15 


.10 


P2 TO-92 


PNP 


to-level 






.15 


.10 


P3 TO-92 


PNP 


medium 


power 




.20 


.15 


P4 TO-92 


PNP 


2N3906 


type 




.15 


.10 


P7 TO-92 


PNP 


high-vo tage 




.25 


.20 


PS TO-92 


PNP 


higher-voltage 




.30 


.25 


AND SOME OLD TRANSISTORS . . . 




1-99 


100+ 


2N2222 TO-18 NPN 






S .25 


,20 


2N2907 TO-18 PNP 






.25 


.20 


NPN TO-92 general purpose 






.08 


.0595 


PNP TO-92 general purpose 






.08 


.0595 


Data on all trar 


isistors and JFETS is now in 


our flyer. 




BRAND NEW ALUM. ELECTROLYTIC CAPS, RADIAL LEAD 




10 


l,W 


35wv 




bOwv 


Imfd 


s . 


10 


S 


.12 




$ .15 


2m fd 




10 




.12 






5m fd 




10 




.12 






lOmfd 




11 




.13 




.16 


30m fd 




12 




.20 




.28 


50mfd 


« 


13 










lOOmfd 


m 


15 




.30 




.45 


200m fd 


* 


20 








.70 


500m fd 


m 


28 




.75 






lOOOmfd 


4 


50 











RGS ELECTRONICS 
3650 Charles St., Suite K ■ Santa Clara, CA 95050 ■ (408) 247-0158 



We sell many tCs and components not listed in this 3d. Send a stamp for our free flyer. TERMS OF SALE: 
All orders prepaid; we pay postage. $1 .00 handling charge on orders under S J 0.00. California residents please 
include sales tax. Please include name, address and zip code on all orders and flyer requests. Prices subject to 
change without notice. 

DISCOUNTS: 10% OFF ORDERS OVER $25.00: 20% OFF ORDERS VER S250.00 



AUGUST 1975 



175 




6 Digit Digital Clock Kit 



Our Engineer said it would be 'Impossible" to sell a Six Digit kit 
for this price. But because of several special super buys we 
made on chips and displays we can offer this unbelievable 
bargain on our Clock Kit. Sure, this price is too good to be true, 
but rest assured, all parts in this kit are prime, first run units. 
Also, all kits are sold with an unconditional money back 
guarantee. 

Hw's What Th0 Kit Inclutl^s: 

t — MM5314 National Clock Chip with socket 
6 — Common Cathode Led Readouts (.25 in. char.) 
13 — NPN and PNP Driver Transistors 
2 — Push Button Switches for time set 
1 — Rocker Switch for time hold 

I ■" P liter cap Transformer for 

4 — IN4001 Rectifiers this kit- $1,50. 

1 — IN914 Diode 

2 — .01 Disc. Caps 
9 — Carbon Resistors 

P.C. BOARD FOR ABOVE - $3.00 each 

All you need to add is a 12V AC Transformer, perfboard, and your 
choice of case. The above parts, if ordered separately from our 
competitors, could cost you as much as $20. Buy from S.D. and 
you'll be happy with our quality parts and ultra fast shipment. 



$Q95 

*F (KIT) 
WITH SPECS. 
POSTPAID 



14 PrN-5For$1 



/C SOCKETS 
16 PIN-4 For$1 



NATIONAL 2K ERASEABLE PROM 
2048 Bit, static unjts, U.V, light eraseable. MM5203. 
Factory prime new units. Speciai — $14.95. 



DIGITA L CLOCK CHIPS B Y NA TIONAL 
FACTORY NEW UNfTS! 
MM5314 — 4 or 6 digits. 24 pin DIP. Use with LED 
Readouts. With Specs. — $3.95 
MM5316 — Alarm chip. 40 pin DIP, S4.44 



TEXAS INSTRUMENTS 8 DIGIT CALCULA TOR CHIP 
TMSO 103NC. Four function. Same style as used In TI 
pocket calculators. Factory new units, with specs. $i .99 
each. 



1AMP 1000 PIV SfLfCON RECTIFIERS 
IN4007. Factory prime devices. 10 for $1 .00. 



741COPAMPS 
Prime, factory tested and marked. Full spec on all 
parameters. Not re-tested, functional only, units as sold 
by others. 
741 CH — TO*5 8 Lead Metal Can ......... .3/$l 

741CV — 8 Lead Mini Dip ..,,,, 4/$1 



SWITCHES FOR DfGfTAL CLOCKS. ETC. 
Rocker style. SPOT, miniature size. 4 tor $1. 
Push Button. SPST N.O. Enclosed, mini. 4 for $1 



SUBMINIATURE TRIMMER CAPS 
Ultra stable. Range: 3.5 fo 18 PF. 2 for $1 



FILTER CAPS 
Dual section, 2000 MFD and 1500 MFD at 30 WVDC, 
Twist Lock. 79c ea. 3 For $2 



NATIONAL VOLTAGE REGULATOR 
Like 7805, 5VDC — 1 AMP output Has TO-220 plastic 
power tab — 99c 



IN414d COMPUTER DIODES 
Same as IN914. Factory prime. 20 for $1 



FULL WAVE BRIDGE 
ByG.r. 1.5AMP800PIV — 75c 



2N706A400MHZ. TRANSISTORS 
Silicon NPN. 1 WATT. TO-18 Case. 5 For $1 



12VDC RELA Y 

DPDT. Heavy gold plated 5 amp contacts 
coiL Limited Qty. 99c 



300 OHM 



723CH PRECISION VOL TAGE REGULA TOR 
Build a circuit regulating the voltage from 2 to 37 volts. 
Complete specs included. One of the easiest to use 
regulators now on the market. 

S,D. Special Introductory Price 
2 For $1.00 



176 



73 MAGAZINE 



1 



S. D. SALES CO. 



28810 DALLAS, 



FAST SERVICE - QUALITY MERCHANDISE 

BARGAINS GALORE - NO BACK ORDERS 

We are SMALL enough to give personalized service, but 

LARGE enough to handle every order swiftly and efficiently! 



INTEL IK 2102 RAM 
Factory prfme, tested units. Factory selected for much 
faster speed than units sold by others. 650 NS. These 
are static memories that are TTL compatible and 
operate off 4- 5 VDC. The real workhorse of solid state 
memories because they are so easy to use. Perfect for 
TV typewriters, mini -computers, etc. With specs. 

$3.95 ea. or 8 for $30 



SfGNEJtCS IK PROM 
82S129, 256 x 4. Bipolar, much faster than MOS 
devices. SONS. Tri-state outputs. TTL compalibfe. Field 
progfammable, and features on chip address decoding. 
Perfect for microprogramming applications, 16 pin DIP, 
With specs. $2.95 ea. 



LM324 — QUAD 741 OP AMP — $1 .50 



NE555 — Timers — SSc or 10 For $6 



709CH — OP AMPS — 4 For $1 



GESCRC106B1 
4 AMP 200PIV. Sensitive Gate. Mc 



MOTOROLA POWER DARLINGTON — tr.99 
MJ3001 -NPN - 80 Voits - 10 Amps - HFE 6000 typ. 
To-3 Case. Ideal for power supplies, etc. We include a 
free 723 regulator w/schematic for power supply with 
purchase of the MJ3001 . You get the two key parts for a 
DC supply for only $1.99. Regular catalog price for the 
MJ3001 IS $3 82 



Type 

2N3904 

2N3906 

2N4401 

2N4403 

2N3638 

EN930 

2N2905 

2N4249 



TRANSISTORS 

Mat. Pot. Vceo Ic Hfe 

S N 40 100MA 200 

S P 40 100MA 200 

S N 40 250 MA 200 

S P 40 250MA 200 

S P 25 150MA 60 

S N 45 50MA 300 

S P 40 350MA 200 
S P 60 



Case 

TO-92 

TO-92 

TO-92 

TO-92 

TO' 105 

TO- 106 

TO-5 



Price 

6/1.00 

6/rOO 

6/1.00 

6/1 

6/1 

6/1 

An 



00 
00 
00 

00 



6/1-00 



RCA HIGH VOLTAGE POWER TRANSISTOR 
100 Watts. 5 Amps. 300 VCEO. TO-3 case. Silicon 
NPN. Mfg. house numt)ered 2N5240- Regular catalog is 
$6. Perfect for H.V. supplies or vertical and horizontal 
circuits. 

SPECIAL - 99c 



HEAVY DUTY TRANSFORMER 
36 VAC, 3.5 AMPS, 115VAC 60HZ. PRI, For power 
supplies or audio power amps. Best quaNly, fully 
enclosed, $4.95 



Our 6 DIGIT CLOCK is not a CHEAP CLOCK 
KIT, only inexpenave* That's why we have sold 
several thousand in the last three months, 
without a single kit being returned for refund. 



ORDERS OVER $15 
CHOOSE $1 
FREE MERCH. 



FREE BONUS 
All clock or calculator 
chips are shipped with 
free socket. 



FAIRCHfLD LED READOUTS — 69c 
FND-70. Common cathode. Right hand decimal point, 
.25 inch character. Prime new units. Perfect for clocks, 
frequency counters, etc. 69c 10 For $6 

Best Readout Buy In USA! 



W PIN SOCKETS FOR FND-70 
An S.D- exclusive. For use with our Fairchiid LED 
readouts. 

29c ea 10 For $2.50 



DO YOU NEED A LARGE, COMMON ANODE 

READOUT AT A FANTASTIC PRICE? 

S.D, presents the MAN-64 by Monsanto - .40 inch 

character, All LED construction - not reflective bar 

type, fits 14 pin DIP. Brand new and factory prime. Left 

D P 

$1.59 ea. 6 For $7.50 



DL 747 JUMBO LED READOUTS 
By Litronix. ,65 inch character. Common anode. Out- 
performs SLA-3. Perfect for giant digital clocks. Only 
20 MA. per segment. Special — $2.60 ea. 



LARGE SIZE LED LAMPS 
Similar to MV5024. Prime factory tested units. We 
include plastic mounting clips which are very hard to 
come by. 

Special 4 ForSI 



PC BOARD MA TERIAL 
FR-4 blank epx^xy boards. 2 oz. copper, 5 x 10 in. Single 
Sided. 

Limited Qty. —$1,49 



MOTOROLA VOLTAGE REGULATOR 
MC1469R. TO-66 9 Lead package For 3 TO 30V 

Outputs. Provides 600 MA direct output or more by 
using an external power transistor. Reg. catalog $4 ea. 
With specs, $1.95 ea. 



MOTOROLA NEGA TIVE VOLTAGE REG 
MC1463R — Like our 1469B above, except for negative 
voltage. Reg. catolog $5. Our price $1.95. 



POWER TRANSISTOR PC BOARD 
Mfg. by Memorex Computer Corp, Board has 20 Power 
Transistors. 10-RCA 2N3585 TO-66 SILICON NPN. 
VCEO-300 IC-2AMPS. 10-MOTOROLA MJE-340. NPN 
Silicon. VCeO-300. Plastic power tab case. Also has 
10-2N2222A TO-18 NPN transistors and 10-1N5059 1 
AMP 200 PIV rectrifiers, plus 32 resistors. LIMITED 
QTY, Board #103. $3.99 ea. 



48 HOUR SERVICE 
You deserve, and will get prompt shrpment. On orders 
not shipped in 48 HRS , a 20% cash refund will be sent. 
We do not sell jur^k. Money back guarantee on every 
item, WE PAY POSTAGE. Orders under $10 add 75c 
handling. No COD Texas Res add 5% tax. 



S. D. SALES CO 

P,0. 80X28810 
DALLAS, TEXAS 75228 



Auaiicrr 197^ 



177 



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SN7400IV 

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€04022 
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CD4025 
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€04031 



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WITH EACH 
S75 ORDER GET A 



FREE 



ONE YEAR SUBSCRIPTION 

KjV I [ the magazine 
for computer PHflEAKS 

S12.00 VALUE 



JAMES 



m 



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LM3aZH 75 

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LM3Q7CN 3$ 

LM3DSH 100 

LUItSCN 1 00 

LU3e9H 1 10 

Ui309K 1 25 

LltSlOCN 115 

LHSUH 90 

1*131 1M 90 

LM3UCN 1 50 

m319fl 1 30 

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tll33(lK 5 1 3$ 

LM32aK 57 1 K 

LHMW 17 1 3S 

t.M320i; 15 1 35 

L1I3I3K5 1400 

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DISPLAY LEDS 



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Electronics 

P D iO)iB22-Belmo&E Ci 94002 



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HV 10 
MVSO 
HV 5034 
liV 5034 
MV 5024 
MV 5024 



5^11 QQ 
6/SIOO 

5/$ioe 

4/Sl.OO 
4/SlDO 
i/$l OO 




178 



73 MAGAZINE 



JAMES AUGUST 

specials 



OVM€hipS« 

iOnO dEgllal A/D ProcfltKir 16.00 

iDffl Analog A/0 Procittor 13.00 

UARTaAy S1(J13A 



121.00 SH 



P. 9 5 Mc3i 



LM301AN 
LH307H 
LUln H 
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LrilEAR JC'5 

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Smwr Op Aenp 

Htparl. VcDfii|i, 

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TiArtT 

Phm JocL losv 

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Fitfition Gtnttttor 



WEWKITS 

TTL Lagic Proba Kit fsjl pir kit 

Diricli TIL livflli. putKi, wiih fni^ 3 rtidoul 

~ " THE KILOBYTE RAM CAAD — 
€dniplti« IK « B M«morv 
'Singti 5V tuppfy 
'* 500^11 Ac cm Time 
'H4fh ^Qrif ImmuiiTty Comp&ntnti 
'Kit Includn Socktti & eoird. S«lfl5 

DIGITAL COWIlTlRyiitT 

4 Eic^i - Min7 OEiplin ^Oifit liKhn 

* T I MOO Caum«r *0n Sc^id OtcinalDr 



*C*ni#l«H pnth Bcurtf 



tZtJSItK 




DI£1TAL VOLTHETER KIT 

0-10 Voh; 31^ dffiti IMin 7) DVU 
KOS L&ID»fn ^-n AC 

Sin r*3"« iH- ajy.93 



4' POWER SUPPLY CORDS 

Black _rt 

.59« ea. 




THUMBWHEEL SWrTCHES 



lALMHICHCMLV 








4 9 • f 




POCKrr CALCUUITOil KIT 

h lumtipn pltif cnnirinr - 
id^nsttble memary with 
ii>dmdu4l recflH - S djgir 
dliplav plus QverlEow - bttliry 
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lichirgt^btci bmtenii - lil 
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iisiimbl« form - inftrurtJMf 

indmlid. 3^' x Sl£" , 

OPTIONS- 

1 15V AC Trinsfornitr 

6 Mch -H" Alk«iiiit B*\mm . . 



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Hvt't t law co^, bq 10 !£ c^Kily 
br«*d6^rd kit wrt^ #11 rhi qmNrr «! 
OT St^drtt and! ttit best of Tht Piow 
B^rd i«ri^ . . ciHiiplne downi te rhf 
lilt nul. 'bhoU «nd scrtw. Incliriltii 
2 OT 3S5 SKlini; 1 OT JSB Bin Strip. 
2 5 wiY bimlrng P05TS. 4 rufaNv fni; 
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SnoiKli r Mi#i 

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Wirve & A^mfalwl IIS V«c SMJS 




50 PCS. RESISTOR ASSORTMENTS $1.75 PER ASST, 



ID OHM- I? OHM TBOHM IB OHM 2? OKM 
3T OHM 33 OHM 39 OHM 47 OHM SS OHM 

gfl OHM g? OHM lOa OHM 17(1 OHM j50 OHM 
180 OHM 2?a OHM 270 OHM 330 OHM 390 OHM 



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IC'S 




KITS 



FUNCTION GENERATOR KIT 




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XR<220«K 



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lnciud«i mcif^olrtfiic f unction gtrhinior IC, PC bD#rd. iM asambly 
iniiiiictron nufiiMl. 

xhzukkb $29.95 

Simt ii X ft -2206 K A abawt ind induttes eifernal cotDpuntnts 

for PC boartf. 

TIMERS 

XB555CP 

Xfl320P 

Xfl-5&5CP 

Xft2556CP 

XR-2240CP 



Monohrhic Tirrser 

Precision Timflf 

Dual 556 Tiniir 

Du9l Timing Circuit 

PrDgrdrr^rnable Counter/Timer 
PHASE LOCKED LGOPS 
XR-210 FSK Demodulator 

KB 215 Hjgih Frequency PlL 

XR 567CP Tone Dficodfir immt OlP> 
XR &67CT Tone Oeiradet (TO 51 
STEREO DECODERS 
XR U JOP PLL Stereo Oecodtr 
XR 1310EP PLL SiCfto Decoder 
XR 1800P PLL Stfreo D^^^dn 
WAVEFORM GEIVERATQRS 
Xf\ 20S Wsvi\arm Generator 

XR-2206CP Monolithic Function Genwaior 
XR 2207CP VDhagt-Conimlled Qicrllator 
OTHER EX ARIC'S 

XR HSBCn Dual t ISV Tracking Regulator 
XR T48aN Duad Line Orivtr 
XR 14B9AN Quad Line RficeJver 
XR 22a3CP Operational M^jltiplier 
XR2211 CP FSK DsmodulatprnTona Oecodef 
XR-22£i Monolithic Propordonel Sarvo IC System 
w/4 ea. Driver TrAnsistor 



&.20 
BM 
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170 

120 

3.20 
120 



185 
5 JO 

570 
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3.73 



^Special Requested Items* 



i0O9 Ptotti«>r 

n012S6i t RAM 

2T02 1024 RAM 

A¥5 1013 UABT 

flC4t»4?K 

<101 

&2B1 



1267 
B13* 

25ia 

25 19 
2524" 

2S2S 

2533 



4{]24F' 

NaT!? 

MCI7«1 

MC4044 

CA3t3IB 

40410 

40673 



TYPE 
IN ME 

mm 

IN75J 

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INHE&B 

IN&Z32 

|N^734 

INb?3S 

IN523fi 

IN4S6 

IN4Se 

IFi4a5A 

IN4001 

^4002 



tMPS-AOS' 

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2N2221 

3N2222A 

2N23B 

2M23$SA 

2N24S4 



400m 
400111 
4tM!iD 
400m 
4QaFr 
400ni 
SOOm 
SOOm 
500ni 
SOOm 

40m 
7ai 

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1 AWP 
1 AMP 



PRICE 

4/T.tKI 

4/1.00 

4/I.QQ 

4/1.00 

4/ 1, OP 

4/1.00 

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E/1.0Q 

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TYPE 

1114003 
1114004 
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W4f48 
iN4l54 
IN4734 
IN4735 
IN4738 
IN473B 
IN4742 
IN4744 
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INM88 



<Raelifl«} 
VOLTS W 

200 P(V 

4{)0flV 

50 



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TRANStSTORS 



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Z»2»0GA 

2N23a7A 

2N30M 

2N3f5l 

2N3725A 

2 N 3903 

2M3S04 



I AMP 
3 AMP 
200m 

lOlTV 

10m 

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3SAWP 

3SAM^ 



2N330fi 

2N3^M 

PN4Z4§ 

PN42S0 I: 

2M44D9 

2115129 M 

2N5T39 

ClOGilSCR 



J/iM£^ 



P. 0. Box 822--Belmont,Ca. 94Q02 

PHOME ORDERS WELCOfJE 

[4I&1 592-8097 



Electronics 



Satitfjction Guarintoid. $5.00 Min, Order. U.S. Fundi. 

Cillfornta R«iid#nts— Add 6% Salts Tax 

Wrlta for FREE 1975 Catitog ^ Data Shaatf .2S« aach 



1 



AUGUST 1975 



179 



f 



round the uiorld 



Meet adventure head on. Shipmates wanted 
wfw yearn to achieve for themselves rather than 
be pampered atx>ard plush, pretentious cruise 
ships. Share this adventure with a small conge- 
nial group In a highly Informal atmosphere with- 
out regimentation or timetable. In this age of 
luxury and self-indulgence our expeditibn offers 
a unique, exciting opportunity. 




YANKEE TRADER 

(Famou* ocaanographic vataaJ) 
Langth 180. Baam 31.5, 1106 ton« 

ft MONTHS - SHARE EXPENSES 




Special Ham Discount! 

Ports of call 

Cope Haitien. 

San Salvador. 
Panama. 
Pitcoirn Island. 
Easter Island. 
Ropo. Tahiti. 
Ahe. Mooreo. 
Galapagos. 
Samoa. Tutu i la. 
Donaer Island. 
Guodaconal. 
Ikilogi. Bali. 
New Guinea. Java, 
Madoaoscar. 
ZanziBor. Beiro. 
Capetown. 
St. Helena. 
Ascension Island. 
Rio. Devils Island. 
Paramariba. 
Martinique. 
Antigua. Exuma. 
Nassau. 



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ease send me your free 'round the world expedition booklet | 

I 
I 

Windjammer Cruises. 




A WIHPiAMUtH IMT£|)^A!iOf*iAL SUBSiDuknT-OrC 



AdOi^ins 



Ct, 



Sitfv 



2m 



I 



P.O. Box 1 20, Dept. 1 2t . Miami Beach. Florida 331 39 



I 

I 
I 
I 

I 



^^^■^^^ 




180 



73 MAGAZINE 








i-^^ , 




Hit the deck in shorts and 
a tee shirt. Or your bikini if 
you want, 

YouVe on a leisurely cruise 
to remote islands. With names 
like Martinique, Grenada, 
Guadeloupe. Those are the 
ones yuuVe heard of. 

A big, beautiful sailing vessel 
glides from one breathtaking 
Caribbean jewel to another. 
And youVe aboard, having 
the time of your life with an 
intimate group of lively, fun- 
loving people* Singles and 
couples, too. There's good food, 
"grogr and a few pleasant 
comforts. , . but there's little 
resemblance to a stay at a 
fancy hotel and youll be 
happy about that- 

Spend ten days exploring 
paradise and getting to know 

congenial people. There s no 
other vacation Uke it. 

Your share from S245. A new cruise is forming now. 
Write Cap n Mike for your free adventure 
booklet in full colon 

SPECIAL HAM DISCOUNT 




JZZl 



Windjammer Cruises. 



A WINDJAMMER INTERNATIONAL SUBSIDIARY * OTC 



Ntm« 



Address 



Citv 



Stale 



Zip 



PNOfW 



P.O. Box 120, Dept. 121 



Miami Beach, Florida 33139 



AUGUST 1975 



1R1 




sijj]TxJDj]i:{ 



mi]?i]\ri 



6 KING RICHARD DRIVE, LONDONDERRY, N. H. 03053 

603-434- 4644 



ITEM D: CRT HIGH VOLTAGE POWER SUPPLY - 
This is a real super CRT High Voltage Power 
supply, providing all voltages needed for any CRT 
Outputs 10-1 4KV DC, plus 490 Vdc, minus ISO 
Vdc, Needs inputs of plus 5,0 VDCf plus 16,0 VDC 
and a drive signal of approx 8 A kHz @ IM vrms or 
more. All inputs/outputs via plug/ jack cables and 
even has a socket/cabie assy for the CRT, A very 
tme tmyat only -$14,95 (incL data) FOB 





ITEM E: LOW VOLTAGE POWER SUPPLY - A real 
brute used to supply all lov/ voltages needed by the 
original 720 CRT Terminal, Input, 117V AC, out- 
puts: plus 16,0 VDC @ lOMA; minus 16,0 VDC @ 
10.0 A; plus 5.0 VDC @ more than 2.0 A, all 
regulated. Mounts on the rear of the Ba^c Chassis 
(Item B) Weighs approx 45 lbs and will be shipped 
with interconnection data for only —$19.95 FOB. 



i»i|.^."i r 



ITEM F: ENCLOSURE AND BEZEL FOR 12" CRT - 
This is the frosting on the cake. All components A 
thru E fit perfectly inside this enclosure, ft Is? 
hinged and can be lifted for easy access to the 
electronics. It will really dress up any project. 
Measures approx. 22 "Lx lfi"Wx 20"Hand weighs 
approx, 10 lbs. Made of steel with a handsome blue 
crackle finish. Get 'em while they last, for — 
$11,95 (incL bezel) FOB. 





ITEM G: ASCII KEYBOARD - This is the ASCII 
encoded keyboard used with the SANDER'S 
ASSOCIATES 720 System Terminal, Plugs into the 
front of the chassis mounting base. Makes a very 
professional Video Readout Terminal combination. 
These keyboards are in like new condition, have 
interconnection data etched on the IC- Diode 
matrix PC board. They can be readily used for any 
ASCII encoded requirement, SutnUar keyboards, 
when available, sell for almost two times the very 
low SUNTROmx price of - $49,95, PPD 



PACKAGE DEAL — For the really serious experimenter we'll make a very special offer — you can 
buy all of the suh-a^emblies hsted above plus a good 12" CRT, a muffin fan for cooling. Well 
supply instructjons for interconnection for all subassemblies so that you can, within minutes after 
receiving thk once-in-a lifetime deal, put an X-Y display on the CRT We'll also include a list of 
possible applications for those with short imaginations! Don't miss out on this real money-saving 
buy; the individual prices for tiie sub-assemblies add up to $127-70, You can buy the entire 
package for a very low package price of — $79:95 FOB. 



182 



73 MAGAZJWE 



We've got a bunch of these fantastic video display terminals . . , and we've got a 
little problem. We promised Sanders Associates that we would sell them as scrap, A 
couple of wires disconnected makes them scrap, right? These VDTs should be great for 
SSTV, for a CW/RTTY keyer terminal, an oscilloscope, weather satellite monitor, or 
even a computer terminal (which they were). We've tested some of these and they 
seem to be near-perfect You aren't fikeiy to find a VDT system like this for less than 
ten times the price . < , so order several right away while we've got 'em. 



»^DiilWliliffiS^^ww$% 



ITEM A: VERTICAL AND HORIZONTAL AMPLIFIER 
Subassemblies — Good for a conservative I50W 
complementary DC coupled output, Freq. resp. 
beyond 2,0 IViHz. Parts alone worth many times 
the low, low price of — $6,95 ea., or both for 
$10.95 PPD 





ITEM B: BASIC CHASSIS AND MOUNTING BASE for 
12'' big-screen CRT. Tube can be mounted either 
vertically or horizontally by rotating front plate 90 
degrees. Comes with base, on-off sw. and intensity 
control, four controls for vert, and horiz. Has 
plenty of room for most any electronics needed for 
your pet project. All subassemblies offered wSl 
perfectly fit in spaces provided. Why try to cut the 
metal yourself? This chassis jmll let you con- 
centrate on the electronics instead of the metal- 
work!! Order now for only - $14.95 FOB, less 
CRT. 



ITEM C: FOUR PC BOARDS CHOCK-FULL OF 
GOODIES - Two D/A converters, one IC-loaded 
logic board, and one multipurpose hoard. We have 
no schematic data for these boards at present We 
will supply any data we obtain to purchasers as we 
get it. Of course when we finally figure out what 
these boards are good for, the price will change 
accordingly. Take the gamble now and well 
provide any data we get free of charge. Buy all four 
boards or just one — $L50 ea. four choice) or all 
four for $5.00. PPD 




;:±^S^??#!f^^=4ti..,.v^.p::-i,-i. 





BANKAMERICARD 




On all pc^paid orders, please ADD $1.50 to cover handling costs. Orders 
shipped same day in most c^es. 

F,0»B. warehouse. Send SASE for literature. 




SUJJTiJDlJJ:! 



m]]pi]!ri 



6 KING RICHARD DRIVE, LONDONDERRY, N- H. 03053 

603-434- 4644 



AURIJST 1Q7F; 



1R3 



TERMS ANt> ALL THAT STUFF: ADD 50* TO ORDERS 
UNDER SlOj ITEMS POSTPAID EXCEPT WHERE INDI- 
CATED. CALIFORNIA RESIDENTS ADD TAX. NO COD. 



NOW.,. CALL mS) 357-7007 24 HOURS A DAY TO 
PLACE MASTERCHARGE OR BANKAHERICARD ORDERS. 





BILL GODBOUT ELECTRONICS 
BOX 2355, OAKLAND AIRPORT, CA 94614 





OARDI f 




KEYBOARD #1 is a noh-muitiplexed typej it 

CAN BE USED FOR APPLICATIONS OTHER THAN 
CALCULATORS (TOUCH TONEj LOGIC CIRCUITS/ 
ELECTRONIC MUSIC). ONE TERMINAL OF EACH 
KEYSWITCH IS COMMON BUSSED^ BUT AN X" 
ACTO KNIFE CAN MKE BOTH TERMINALS OF ALL 
KEYS ISOLATED FROM ALL OTHER KEYS* A VERY 
VERSATILE KEYBOARD, COMPARABLE TO OTHERS 
SELLING NATIONALLY FOR FIVE BUCKS AND UP, 

KEYBOARD #2 is a multiplexed type^ suita- 
ble FOR CALCULATOR + OTHER APPLICATIONS. 
FOR LESS THAN TWO BUCKS YOU GET ONE KEY- 
BOARD WITH CHARACTERS PRINTED ON THE KEYS 
AS SHOWNj ALONG WITH AN IDENTICAL MODEL 

THAT HAS NO PRINTING ON THE KEYS. 




62.95 






Qiaja 





*■ « *■ 




2/61.95 




_ THESE ARE 
7 SPST SWITCHES^ 
PACKED INTO A DIP PACKAGE. 
GREAT FOR SET AND FORGET SWITCH- 
ING APPLICATIONS, PATCHING^ SIGNAL ROUT- 
ING + DOZENS OF OTHER USES. THIS ITEM IS 
TO SWITCHES AS TRIHPOTS ARE TO RESISTORS; 
BEST OF ALU THE PRICE IS RIGHT. 



HOBBYWRAP TOOL — WHY SOLDER YOUR PROTOTYPES? WIRE WRAPPED 
CONNECTIONS PROTECT COMPONENTS FROM HEAT. ARE EASILY MODI- 
FIED FOR CORRECTIONS OR CHANGES. MAKE CONNECTIONS THAT ARE 
BETTER THAN SOLDER. AND CAN SPEED UP THE TIHE REQUIRED FOR 
ASSEMBLY OF C0P1PLEX DIGITAL PROJECTS. IF THE HIGH COST OF 
WRAPPING PUTS YOU OFF. LOOK AT OURS.. YOU GET THE TOOL (RE- 
CHARGEABLE SO YOU DONT HAVE TO DEAL WITH TRAILING CORDS IN 
TIGHT PLACES). BIT. CHARGER. NICADS. AND INSTRUCTIONS. 



oiiywumip 








1ftd 



73 MAGAZINE 




u 



n 








iti 





THIS KIT HAS GONE OVER VERY WELL. COMES 
LESS CASE AND TRANSFORMER, BUT INCLUDES 
EVERYTHING ELSE. PARTS MOUNT ON MOTHER- 
BOARDj READOUT + LENS (10UNT ON DAUGHTER- 
BOARD. AND THE READOUT MAY BE RENOTED. 
THE READOUT-BOARD- LENS COMBINATION ALONE 
HAS SOLD FOR $11.95 NATIONALLY. 

TimE BRSE Krr $1195 

IF YOU WANT TO USE OUR CHEAP CLOCK — OR 
OTHER DIGITAL TYPES — IN THE FIELD. TRY 
OUR HICROPOWER 60 HZ TIME BASE KIT . IT 
DELIVERS A STABLE. CRYSTAL - CONTROLLED 
SOURCE OF 60 HZ TIDING PULSES. USES CHOS 
LOGIC: WORKS FINE WITH A 9 VOLT BATTERY. 



COMPUTER STUFF 



ROM PROGRAMfllNG 



«««'»««*«»#•#«*##*•««««««»#«#«##»«»«*««*« 



«»#*•»«#-»»««««»-»«*»««*#»#«*«««#«»««««»«* 



WE CAN PROGRAM YOUR 5203s. 1702s. AND OTHER ROMs. COST 
IS $7.50 FOR ONE. OR 10 FOR $35.00. CALL OUR 24 HOUR 
PHONE LINE TO REQUEST HEXADECIMAL CODING FORMS, 

80Q8 MirRQpRnrFSSOR*********************************** 
THIS EXTREMELY POPULAR PROCESSOR CHIP FORMS THE BASIS 
FOR 8 BIT MICROCOMPUTERS. GAMES. SMART TERMINALS. AND 
OTHER COMPUTER ORIENTED APPLICATIONS. WE'VE GOT THEM. 
AND FOR ONLY $27,95, 





BILL GODBOUT ELECTRONICS 
BOX 2355, OAKLAND AIRPORT, CA 94614 



RESISTOR ASSORTMENT 

OUR POPULAR RESISTOR ASSORTMENT IS BACK 
IN STOCK AFTER A SHORT VACATION. STILL 
CONTAINS 500 OR MDRE QUARTER-WATT RESIS- 
TORS, WITH A WIDE RANGE OF POPULAR VALUES, 
LEADS ARE CUT AND FORMED FOR PC MOUNTING. 
IF YOU PREFER HALF-WATT RESISTORS, WE CAN 
STILL MAKE A DEAL. 300 OR MORE HALF-WATTERS 
PER ASSORTMENT. 

ASSORTMENTS; k WATT $3.95j ^ WATT $1.95 



DIODE SPECIAL 

LEADS CUT FOR PC I 
HOWEVER, THE CUTTI 
ING JOB ISN'T THE 
IN THE WORLD, IN 
QUINN SAYS THEY'RE 
SCHHOOGILY. STILL 
ELECTRICALLY PERFE 
NEW 1N4003 TYPE DI 
PERFECT FOR HOBBYl 
COMPUTER FREAKS- 



NSERTlONt 
NG + BEND- 
GREATEST 
FACT, MIKE 

KIND OF 
, THEY'RE 
CT, BRAND 
ODES, 
STS AND 




DIODE SPECIAL: 100/ $2.^9 



PC BOARD STOCK 

THESE ARE SINGLE SIDE COPPER CLAD PC BOARD 
STOCK, .050 INCHES THICK, AND 9 X 14. S 
INCHES TOTAL SIZE, MAY HAVE NOTCH IN COR- 
NERS, OTHERWISE NEW CONDITION. 

PC BOARD $1.50/SHEET. 2/ $2,95. ADD SHIP- 
PING. 1 LB. PER BOARD, 



POWER SUPPLY news: OUR 12 V0LT--8 
OF OUR ALL-TIME BEST SELLING KITS, 
AND IT TESTED OUT SUPERBLY ON THE 
THE PRESENCE OF A STRONG RF FIELD 
BEEN OVERLOADED, K5IUY^ IRV SANDERS 
INTO THE CURRENT LIMITING NETWORK 
PLY ADD TWO -001 CAPACITORS FROM P 
OUTPUT OF THE POWER SUPPLY. THIS 
YOU DON'T HAVE ONE OF THESE HANDY 
SHIPPING FOR 8 POUNDS. GIVE US YO 



AMP POWER SUPPLY, FEATURED IH THE MAY ISSU 
WE RECENTLY IMPROVED THE UNIT BY ADDING A 
BENCH. HOWEVER, A FEW PEOPLE WROTE US SAY I 
^ THE POWER SUPPLY SEEMED TO MYSTERIOUSLY 
^ WROTE IN TO SAY THAT HE FIGURED THE PROBL 
OF THE 723. WE WOULD SUGGEST THAT OWNERS O 
IHS 2 AND 3 OF THE 7 23 TO GROUND^ AMD A .01 
JCEEPS RF AWAY FROM THE CHIP^ SOLVING THE PR 
BENCH/LAB/EQUIPMENT SUPPLIES, THEY'RE STIL 
UR STREET ADDRESS SO WE CAN SHIP IT UPS. 



E OF 2J. MAGAZINE, IS ONE 
PRECISION 723 REGULATOR^ 
NG THAT WHEN OPERATED IN 
SHUT DOWN^ AS IF IT HAD 
EM WAS DUE TO RF GETTING 
F OUR HEFTY 12 VOLT SUP- 
DISC CERAMIC ACROSS THE 
OBLEM, IF BY ANY CHANCE 
L AVAILABLE FOR $20,95 + 



OTHER NEWS : 
TYPEWRITER, 



REMEMBER THE "WE-NEED-A-NEW-TYPEWRITER" 
THANK YOU VERY MUCHl 



SPECIAL OF A FEW MONTHS BACK? WELL, WE GOT THE NEW 



AUGUST 1975 



185 




Tllnoibeu 



mg^t€,r<^^^ 



ooos 

and 
ENDS 




We have //'mi ted quantities of the following goodies, which we 
offer at a cut rate price to ma/<e room for more goodies. 




MOTRACS U43HHT-1100 152 to 162 MHz, thirty Watts output. Transis- 
torized receiver and power supply. Trunk mount, with cables and control 
head. Regularly $240.00 only $200.00. 

TPOWER U43GGT-3100 152 to 162 MHz, thirty Watts output. Transistor 
power supply. With private line squelch. Trunk mount with cables and 
control head. Regularly $145.00 now only $125.00. 



MOTORCYCLE RADIOS D33BAT 152 
Transistorized receiver and power supply, 
cable. Only $50.00. 



to 162 MHz. 10 Watts output. 
Front mount, less mike & power 



Quantities are limited, please specify your second choice. 

SEND A CHECK OR MONEY ORDER TODAY TO 



DU PAGE FM INC. P.O. Box 1 Lombard, III. 60148 

(312)627 3540 



TERMS: All items sold as is. If not as represented return tor exchange or refund (our option) 
shipping charges prepaid within 5 days of receipt. Ilfinois residents must add 5% sales tax. 
Personal checks must clear before shipment. All items sent shipping charges collect unless 
otherwise agreed. Accessories do not include crystals, relay or antennas. 



186 



73 MAGAZINE 




7- Segment Readout 
12-PIN DIP 

Three digits with right-hand decimal 

Plugs into DIP sockets 

Similar to (LITROKIX) DL337 

Magnified digit approximately *1" 

Cathode for each digit 

Segments are parallel for multiple 

operation 
5-10 HA per segment 
EACH Sl,75 fl '1? DIGITS) S6.00I 



RCA Numitron 

SPECIAL: 5 FOR $20.00 

DR2010 




Irff 



1024 Bit Memory 

1024 Bit Fully Decoded Static MOS 
Random Access Mearory 

-fast access eSOns 
*fully TTl compatible 
-n channel silicon gate 
-single 5 volt supply 
-trt-state output 
-1024 by I bit 
-chip enable input 
-no clocks or refreshinq 
required 

Brand New Factory Parts 

16 PIN ni? Each S5,tK) 
8 for S34.95 



11C05 Falrchild IGHz Divide By Four 

-DC to 1000 Jtiz operation 

-AC or DC coupled 

-Voltage compensated 

-TTL or ECL power supply 

-50 ohm drive output 

-Lead compatible with Plessy SP613 

-True and complement ECL outputs 

-14 pin DIP 

*Data and application notes 

Each S49,55 



Power Supply SPECIAL! 

7Z3 DIP variable regulator chip 1 -40V, 
+ or - outputs 150 MA lOA with exter- 
nal pass transistor--with diagrams for 
inarty applications, 
EACH £1,00 10 FOR $8.95 



5001 Calculator 

40-Pin calculator chip will add, sub- 
tract, multiply, and divide. 12-digit 
display and calculate. Chain calcula- 
tions. J rut credit balance sign out- 
put. Automatic over-flow indication. 
Fixed decimal point at 1, 2, 3, or 4. 
Leading zero suppression. Complete 
data supplied with chip, 

CHIP hm DATA .. .OSLY S2.49 

DATA ONLY (Refundable)... SI. 00 
5002 LOW POWER CHIP AND DATA $12.95 



High Quality PCB 
Mounting IC Sockets 

8-PfN. 14^Pin, 16-Pin and 24-Pin PCB 
mounting ONLY— no wire wrap sockets. 



O— rtn, •«•*■**. «*»«.) . ^^ 



14-Pfn ...$ .26 

16-Pin,,,,. *.*$ ,30 

E4-Fin $ .75 

40-Pin ..,$1,25 




v-^^i Dal^ Trimmer 

-12 turn trimpots which plug 
into a DIP socket 
-5K and 200K 
-%" X k" K %" 
-4 leads spaced .3" x .2" 
Each SI. 00 10 for S8.95 



1000 MHz Counter 



All IC's are new and fully tested- Jj<?ads 
ajc« p la tea Witt gold or sQlder* Orders 
foe IS, 00 or more i*ill fa« shipped prepaid 
Add S .iS for handling and postage for 
snftllvr orders; residents of California 
3da sAlcv tax* IC orders nare ■hipped 
Within 2 vorkdays — kits are stiipped with- 
in 10 days of refceipt ot ora&r*. $10*00 
minimsn on C<Oh.d.*s. 

Mail Orders to; phone 
P.O. Box 41727 

Sacramento, CA (916) 334-2161 
95841 

BRBVLOn 




Money back guarantee 

on ail goods! 



HV50 Red Emitting 
10-4 MA 2V 




MV5024 Red TO-18 
High Dome 




MVIOB Visible Red 
5-7 MA fa 2V 



'S 



$ .20 

10 FOR $1.25 



$ .35 
10 FOR $2.95 



S .30 
10 FOR S2,50 



CD4001 
CD4002 
C04011 
CD4012 



CMOS 

.45 C04023 $ .45 

.45 74C20 .es 

.45 74C160 3.25 
.45 



25K Trimmer 

PRINTED CIRCUIT BOARD TYPE 
EACH $,20 10 FOR $1.50 




I 




"■i^n ' 



Rectifiers 

VARO FULL-WAVE BRIDGES 
VS447 2A 400V 
VS647 2A 600V 



$ .90 

$1.10 



MR810 Rectifier 50V 1 A S .10 



Special 81!' Hex Inverter 

TIL DIP Hex Inverter; pin interchangeable with Sn 
7404- Parts are brand new and branded Stgnetics 
and marked "811." 

EACH $ ae 

DATA 10 FOR 1.50 

SHEET 100 FOR 14.00 

SUPPLIED 1000 FOR 110.00 




1 AMP RECTIFIER 

EACH $ ,15 
SALE 10 for $1.00 



1N4007 IKV PRV 









H 



5 



J> 



MAN 4 7-Segnient, 0-9 plus letters. 
Right-hand decimal point. Snaps in 14- 
pin DIP socket or Molex, IC voltage re- 
quirements. Ideal for desk or pocket 
calculators! 



EACH $1.20 



10 OR MORE $L00 EACH 



3'Anip Power Silicon Rectifiers 

MARKED EPOXY AXIAL PACKAGE 



PRV 
100. 
200, 
400, , 
600, 



.r ^ * ♦ 



PRICE 
* ■ . ^^ . ^ u 

as 

,18 
.23 



# A . . * 



PRV PRICE 

1000 .40 

1200 50 

1500,-..- .65 



DiOD£ ARRAY 10-iri914 silicon 

signal diodes in one package. 20 
leads spaced .1**; no coTrmon connec- 
tions. 

EACH.... 4 ^29 
10 FOR $2.50 




7^00 

7^H00 

7^01 

74HOt 

7402 

7403 

7404 

74BO^ 

7405 

7406 

7408 

74H08 

7410 

7413 

7417 

7420 

74L20 

74H20 

74H22 

7430 

74E30 

74L30 

7440 

74H40 

7442 

7447 

7450 

74H30 

7451 



.20 
.30 

• 20 
-25 
.25 
,25 
,25 
30 
,30 
.40 
*30 
,30 
,20 
,75 
.40 

• 20 
,30 
,30 

• 30 
,20 
,30 
,30 
-20 
,30 

UOO 
1.50 

.30 
.20 



74H51 

7433 

7454 

74L54 

74L55 

7460 

74L71 

7472 

74L72 

7473 

74L73 

7474 

74H74 

7475 

7476 

74L78 

7480 

7483 

7489 

7490 

7492 

7493 

7495 

74L95 

74107 

74 145 

74 180 

74193 

74195 



.25 
.20 
,20 
.25 

• 25 

• IG 

• 25 
,40 
,60 
,35 
,75 

• 45 

• 75 
*S0 
.55 
,70 

• 50 

• 70 
3,00 
1.00 

.65 
1,00 

,65 
1.00 

,35 
1.25 
1,00 
1.50 

,65 



CD -2 Counter Kit 

This ki t provides a highly sophisticated display 
section inodule for clocks, counters, or other nu- 
merical display needs. The onit is .8" wide and 
4 3/8" long, A single 5*volt power source powers 
both the ICs and the display ttibe. It can attain 
typical count rates* of up to 30 MHz and also has 
a lamp test, causing all 7 segments to light. Kit 
includes a 2-sided (with plated thru holes) fiber- 
glass printed c1 rcui t board, a 7490, a 7475, a 
7447, a DR20iO RCA Numitron display tube, complete 
instructions, and enough MOLEX pins for the ICs,.. 
NOTE; boards can be supplied in a single panel of 
up to 10 digits (with al 1 Interconnects); there- 
fore , when ordering* please specify whetlrer you 
want them 1 n single panels or in one multiple 
digit board* Not specifying will result in ship-^ 
ping delay. 

COMPLETE KIT ONLY $10.95 
FULLY-ASSEMBLED f^^^:;- 
UNIT $15.00 r^-im im^im 



I: 



S^T 




Boards supplied separately ^ $2.50 per digit 






7400 Series 



DIP 



L I N E A R S 

NE555 Precision timer , 90 

NE560 Phase lock loop DIP. • 2-95 

NE561 Phase lock loop DIP***^**,*,**^ ,3.00 

NE565 Phase lock loop .,,..,,...•••,••, 2. 95 

NE56S Function generator TO-5 ,•••,*••, 3,50 

f{E567 Tone decoder T0*5 ,.•.,,.•••'., ,^* 3,50 

709 Popular Op Amp DIP • -40 

710 Voltage comparator DIP • .60 

711 Dual conoparator DIP ..,•. -45 

723 Precision voltage regulator DIP 1.00 

741 Op amp TO-S/MINI DIP 45 

748 Op Amp TO-5..... 80 

CA3018 2 Isolated transistors and a Darling- 
ton-connected transistor pair 1-00 

GA3045 5 NPN transi stor array • — * , . . 1 .00 

LMIOO Positive DC regulator T0-5._, 1.00 

LMIOS Voltage regulator ,...• 1.25 

LM302 Op Amp voltage follower TO-5 1-25 

LM308 Op Amp TO-5. , - 2^00 

LM309H 5V 200 HA power supply TO-5....* . 1,00 

LK3Q9K 5V lA power supply inodule TO-3* , 1,00 

LM31I Comparator Mi ni ]*,*•..* — ,.,,,, 1.75 

LM370 AGC ampl i fi er ....,•••*...•.•,•».*,.* * 1.75 

LM380 2-Watt Audio Amp. .,.,...••••• ••• 1.7 5 

LH1595 4-Quadrant multiplier, p .»-•***.**•.- . 1*70 
HjC153oT Op Amp ,••#.. ..*,,-*> •.,.,.•••*# i,aD 



h 



SINGLE CHIP ASCII ENCODER 



'•j 



Desk top calculator by well 
known mfgr. These are rejects, 8 
digit, 4 function^ liquid crystal 
dkplay. Fully assembled^ some 
factory reject, some customer 
returns. Most are repaired in a few 
minutes. Sold "as is." Ship wt 3 
lbs. 

AC model $10 each 3 for $26.50 
Battery portable model $1 1 each 
3 for $30-00 



COLUMBIA 4 CHANNEL SQ 

Solid state SQ 4 channef adapter, 1 amps built 
in. Decodes 4 channel or synthesizes 4 channel. 

$20.00 



LED READOUTS 5/$1.00! 

The price is not a mistake. We have some hobby 
variety with some segments out. Ukinbuyem 
for as low as 5 for $1 .00 



DUAL 16 BIT MEMORY 

Dual 16 bit memory* serial MOS by Phiico TO-5 
case, brand new with 2 page specs. 

#PLR 532 $1.00 each JlO/12 



A hot item today. We furnish full data booklet 
with each order, $1 Q each 3 for $25^0 



8 CHAN MULTIPLEX SWITCH 

Solid state 16 pin IC MOS. 8 channel w/output 
enable control & one-of-eight decoder in chip. 
With data. Fairchild 3705. . .$5.00 



RC OSCILLATORS 

16 pin IC chip contains 4 RC osc. Ideal for 
touch tone encoder. TCA 430. . .$5.00 



PHOTO-STROBE 

Made for Instamatic but useful on any camera 
with instructions provided. Info also on trick 
uses, automotive strobe, slave strobe, automo- 
tive strobe, Psychadelic repetftive strobe, etc. 
Complete with charger & Nickel Cadmium 
batteries. 

$9.00, 3 for $25,00 



P-A-iJ 



Beautiful AM*FIVI Stereo Multiplex radios made 
to sell in the over $100 range. Picture shows 
typical unit. Solid state. AC povA«red, nr\ade for 
famous US manufacturer. Ship wt 10 lbs. 
$35,00 



AM-FM RADIO 

For console instaflation, w/face plate, no 
knobs. Stereo amplifiers for tape or turnable 
playback. $15.00 

Pair of matching speakers w/xfmrs for above 

$5.00 



CALCULATOR CHASSIS 

Fully assembled pocket calculator chassis with 

calculator chip. Uses LED readouts not includ- 
ed. $5.00 



BELLTONE PAGER 

Genuine "Ma Bell" bett clip 
radio receiver beeper. Picks up 
specific radio signals in 35 
MHz area, encoded by internal 
reed encoder. Seems to be a 
"natural" for construction 
jote, In-plant callmg. An inter- 
esting experimental gadget. 
Self contained antenna, adjust- 
able coding by shifting wires 
on coding module, 
^P-125 $5.00each,6/$25.00 



Please add shipping cost on above. 



P.O. Box 62 

E. Lynn MA 01904 



188 



73 MAGAZINE 



1 



KEYBOARD $35.00 

One of the nicest keyboards we've found. Mounted in 
modern design wood grained enclosure for desk-top use- 
Magnetic reed relay bounceless keys witches, Encoder board 
mounted within. Fine Biz. for Morse Code Generators — 
TV Typewriter — computer terminals, etc, 

7lb#SP'153L$35.00 



. n titx 



) 



1 



f^ 



GENERAL PURPOSE POWER SUPPLY 

Well designed transistorized, regulated power supply with 
many uses. Each voltage adjustable by pot* Each voltage 
fused, 115 volts ac input. Output (minus) 12 volts at 1/3 
Amp, 12 volts (plus) at 3 Amps, 6 volts at 1 Amp. Three 
output voltages. Many uses • , . as battery charger, op amp 
(plus & minus 12 volts), 5 volt logic (adjust 6 volts to 5 
volts), operate your car radio, tape p!ayer, CB set in the 
house, etc. A commercially built supply for less than the 
price of kit, 

101b #SP-1 52L $1 2.50 5/$50 



AIR COMPRESSOR $22,00 

Diaphram compressor brand new surplus from the conrv 
puter industry. Built-in 115 volt ac motor ball bearing for 
long life. Puts out 17 RSI with volume 0.7 SCFM. For 
general paint spraying, air cleaning, bubble bath for PC 
etching tank, etc. Many uses in lab or home. 

14lb#SP-148LS22,00 







ANTIQUE SOUNDER 

Takes you back to the Pony Express days. A genuine 
antique relic dating back to the old days. A real beauty, 
polished brass, wood base, bright and shiny new despite its 
age. In original packing as issued to the US Navy Dept. 
Already worth more than our asking price. Makes an 
unusual gift or desk top conversation piece for the man 
who has almost everything. 

#SP-115$15.00 2/$25.00 



SPERRY 9 DIGIT DISPLAY $2.50 

180 volt 9 digit, 0-25 inch height character. Brand 
new and we include free with each, the $K50 
mating socket. The price an astounding new 
low . . . $2,50 

#SP- 145 $2.50 5/$1 0.00 



I I t I I I I I t I I I t I t I n 



u u u u u u u u u 



Please add shipping cost on above. 

P.O. Box 62 

E. Lynn, Massachusetts 01904 



CATALOG 



AUGUST 1975 



189 



I 




2000 



F YOU'RE GETTING 



SOMETHING GOOD 
GET A LOT OF IT I 

THE MULTI-2000 
S A LOT OF RADIO 




FEATURES 

• PLL synthesizer covers 144-148 MHz in 10 kHz steps 

• Separate VXO and RIT for full between-channel tuning 

• Simplex or ± 600 kHz offset for repeater operation 

• Three selectable priority channels 

• Multi-mode operation (CW/SSB/NBFM/WBFM) 

• Built-in AC and DC power supplies, noise-blanker squelch and rf ^in control 

• Selectable 1 W or 1 0W output 

• Separate S-/power and frequency deviation meters 

• Built-in test (call) tone and touch-tone provision 

• Excellent sensitivity (.3 uV for 1 2 dB SINAD) 
•Superior immunity to crossmodulation and intermodulation 

• Introductory price: $695. 



TUFTS 



^adio Electronics 



386 Main St., Medford, Mass. 02155 



LOWEST PRICES INPOiy PAKS SIVt/iSHES 

USA ^CALCULATOR' PRICES 



9-FUNCTION, 8-DIGIT 
MEMORY CALCULATOR KIT 

W% the easiest itiultl- 
function icit today! 



• DOUBLE IMCMORY 

* Percent. Constant, 
Olspiay Restore 









'^S 



<&/ 



i^/ 



4 ■'Function 
Arlthmctle 
11 KEYS! 



EASV TO PLT TOCETHERt Yoa b*i n i» . . immjEine 
hii rrsiMnri. raf^ftcitom, bt|t It QMLY REOtflltCS 3 
C*4IPS 0]»d • itCADOUTI Mow'* that r<jr itmplicity? Th^ 
2 Mi-mtjir.^ kryfl ar« MS Memory 5>ii>rflev ind MR 
Mrriifi'ry Ht^mU ^reqaireK very liulr wk^Mw in% } . Thr 
diwiilay rentorp kry iji lo «onsej-v« bauery lii«. Your 
rihpluy on rmnrl shuiiii nfT 2S svcontli After thr Inal 
jn^rRtion. iiy ^eprc^Mjnif ''D" kty, th^ dj^pUy is 
r4«murtd] UrnvB tl N rrll hnlti^rif^s. Red d#«i^»l ApihtKr* 
<:>n left %a thow when batter^ea ne«d rvplKf *(n#ni or 
cHwrfinit' Kai l>ecifna1, CI* at, Conttiiat. Ferceiil. Vnd 
■J- 1 III me tie key r#d, vrhiir uid blue ralori. Liithtwejjrtll. 

EiorkfL 3i*# 5*/4 X ,1 X *2* «i back aidel k ll'** 
rtiflt side Qf aQ#TtUr dlflpLay paji#l btiwk eu«. Uiivy 
uflit for busiitrc»^ &chcKil, name. &ad for th« ymjtac^iler*. 
^Y\pm inta any pocket. briieFcitAe wjth «ac«. Ea»y-tn- 
una^^mtajiii ptctCifal miiruclioo b^oklal and ti^^w-lo- 
Uiir brmk AC/DC t*«f 

KIT tNCLUDESt caj^e, 32 -key kerbodfd kit. ON 'OFT 
liwuilch {pan fjlf keybojkrd Jf PC boafd, driver and memnpy 
1 iikulaLnr rhUn», '.t-dif^ii "bubble" ninftnmf<^r L£D nrfftV, 
iirrny Ckble, AC adupUr Jack & wJreB+ haLtery case. 6 
buitery cnrd tiiAyA&y, ^nntrUrlioa and pict[»riil at«|9*by* I 
Kiti*n roRstriirtir^ni booklet, ^^^^^ 



MICROPROCESSORS! 
ROMS! RAMS! 
MEMORIES! 



n &O08 Microprocessor - .* ,, ,*44,00 

n »0©0 Sup«r BOOS 250,0O 

□ 2102 1024 Biaiic RAM 3.#5 

n 1101 256 bit KA.V1 l.SO 

G 1103 1024 bh RAM a.»5 

□ MMS260 1024 RAM ...... 2,95 

n MMS2e2 204H bit RAM , .. 6.50 

n 2513 Chftraflc^r generitior . . 12.50 

D MM5203a Erace»ble PROM . 19,9S 

□ MMS202Q Eraeeable PKOM . 1».95 
D 1702A Eriiceable PROM ... 19,95 

Prof(r*imma&le ROM . . 2.95 



D mM oc S-VOLT NICA0 
W**'^^ POWER PAK 

Jncludea 4 ^'A'' celi nic«d 
butteries ho^iced up tD l^tve 
yon G-voIta for ail typisa of 
enerffy u^es. The beat bat- 
terlea to^de. Rechfirg-eiibt«^ 



LED MITY DIOIT "DCM'S 



ri 



58.88 



Ri-;AlK>rT ChLir 
DMAN-I .27 h. 
D MAPi-4 .i»h. 

n7<i4-» ,^%h. 

DfLA-t* .33 11. 
r]ltAH€«.4 b. 



Maker 

Monaaata 

iiviiiaMta 

Larefilc* 

LJIr^alc* 

Oa>c aa 

liea*anfa 



''Digital Coimti[is McHluJeA" oittpcr- 
form uiy other OCM vn the tti&rket today. Mof? I«a- 
lures Unm ever before! Not iaa«oii«, not jEicaj3de?u:e^&*t 
nat Biaic but the mod em LED. Cbooae from aucli fanioi,ia 
mknulKCturera »% Mvnaanto'a MAN^K MAN'4, Litronica 
707 and 7 04, Opcoa'^ KLA- 1 tthe lant 4 bavins ehw^ac- 
tsr hrJirhta of 0,33 at no extra charfeK Each kit, Jn- 
cludtK axZ" n.e board with finite ra for a FHKK edjce 
cannecftar, am#-mountinK dip jacket, LKD readout oi 
your choice, rmlnturs, \i iCft. and Molex connectora 
{tbia ELIMINATES .SOLDERrKf; YiWK IC/^i aiHl 
bodklet. INCLUDES PC. CIMC CONNCCTOR niCEl 

• Pin-for-pm MAN-l."* Ftn^for-pin MAN-4^ ele*. thar. 



Q Same as above except uses MAN-6...,$9.§5 CH«rwct*r 5i»£ O^^ 



Tim*^^ 



0i% 



□ 



Oual 

741 



for 



Siilt^ jj0t»d ti 



OCT 



S. 197 



j:^;;^^EYBOARD kit o $4.95 

Kit indudea 4 x ZVi" G-10 glass etched pc board, 
with 10 OAK "smooth touch" white keys with bluck 
numerals, plus diasram on "touch tone encoder". Makes 
many "keyboard systems" readily available. Q-to- 



y^*vi 



XENON 
FLASH 

STROBE 

TUBE 



MONSANTOl XCITONI 
LITRONIXI OPCOAI 



n 



$1.95 




BUY ANY 
TAKE 15% 

BUY 100 
TAKE 25% 



(SN7400 

ISN7401 

ISN7402 

ISN7403 

SSN7404 

1SN7405 

JSN7406 

3SN7407 

] SN7403 

] SN7409 

3SN7410 

] SN741 1 

3SN7413 

1 SN7414 

3SN7416 

] SN7417 

:SN7420 

3SN7412 

3 SN7423 

:iSN7425 

1 SN7426 

3 SN7427 

:3SN7430 

3SN7432 

3SN7433 

PSN7437 

OSN743S 

QSM7440 

DSN7441 

DSN7442 

nSN7 444 

Q 5ISI7445 

D SN744€ 

□ SN7 447 

DSN744S 

aSN7450 

DSN7451 

DSN7452 

DSN74S3 

aSN7454 

□ SN745S 

nSN7460 



$.16 
,16 
*16 
.16 
.19 
.19 
.35 
.35 
.19 
.19 
,16 
.25 
.59 
1.65 
.34 
,34 

.16 
,45 
,29 



,29 
.25 
,29 
,16 
.25 
.49 
.34 
.34 
.16 
1,00 
,70 
K25 
.89 
1.15 

.99 
.99 
,16 
,17 

.17 
,17 

.17 

.22 

,17 



aSN7462 

DSN7470 

aSN7471 

DSN747 2 

DSN7473 

DSN7474 

aSN747 5 

aSN7476 

DSN7478 

n5N74ao 

□ SN7481 
aSN74B2 
aSN7 48 3 
D SN748S 
QSN7486 
D5N74S8 
aSN74S9 2.45 
aSN7490 ,59 
DSN7491 1.10 
DSN7492 .|| 
DSN7493 -5f 
aSN7494 -95 
aSN749S .79 
DSN7496 .79 
aSN74lOO 1.40 
DSN74104 .44 
nSN74l05 '** 
aSN74l06 
DSN74107 
QSN7410S 

D SN74112 
aSN741l3 
D SN74114 
DSN74121 



44 
,52 
.44 

d9 

.89 
.89 
.89 
,49 



DSN74122 
DSN74123 

DSN74125 

nsN74l26 

asN74l32 l-^i 
asN74l40 2.10 

DSN74145 1-05 
DSN74148 2,25 
QSN74150 .98 

□ SN74151 .75 

□ SN74153 .90 
DSN741S4 1.35 
DSN74155 ,95 
DSN74156 .95 
DSN7 4VS7 .95 

I □SN74158 

I DSN74160 
nsN74l61 
□ SN74163 
DSN74164 1.50 
DSN74165 1.50 
GSN74166 1.50 
nSN74l73 1,45 
aSN74l74 1.39 
OSIH7 4175 1.30 
DSN74176 1.20 
aSN74l77 1,20 

D5N74iaO ,|5 
DSN741S1 2.98 

DSN74182 .74 
nSN74l84 1 98 
nSN74l85 1*98 
aSN74l90 1.40 
DSN74191 1,40 
DSN74192 1.2| 

nSN74l93 1-25 
QSN74194 1.20 

nSN74l9S .85 
nSN74l96 1 80 
DSN74197 .90 
□ SN74199 1.75 
aSN74200 4.S5 



**BUASTAWAJ" 

OH 1N4000 

RECTIFIER PRICES 



A f !!Taa-x lOO 10 lo*' 85« 
BlHMOT 1000 10 tor 1.29 



V 



5 for %t 


.340X.2 

Jiifnbo 

Q R«d 

U Y#JloW 
D Amb«r 
□ CI«Br 


.240X.200 

Mediiim 
O R«i 
a Yellow 
U Gr«eri 
n Amber 


.340X.160 

Medium 

n R»d 

U Ywllowr 
U Amb«r 


.aiox.ias 1 

Mtcm 

G Red 

U Velio* 
Q Amber 



Micro (Axial) MV-50 style 

D MV-SO Clear , , ♦ * 10 for SI. 
G MV-SS Red 6 for $1, 



7-SEGMENT READOUT SALE! 

• Up to 20 mils p«r MS. at 9V, mtm*\ 

• Alt fit Into 14-plii IC ««k«t. 



NATIONAL 
LM-340T VR'ft 

• TO 22Q Zmmm - 1 Amm 
■ POSJTIVC ViM.TAGC 

$1 .75 Each 

LM-34d-(l5T 5 V 
LM-340'Oer 6v 
I.M-340<QeT 8 V 
LM.:I40.12TI2 V 
Lfl4'340.l5TlS V 
LM-340 l0Tia V 
LW-34Q^24r24 » 



TRIACS! 
QUADBACS! 





Typs 


sua 


C<»lor 


Saie 


3 for 


D 


MAN'l 


.27 


Red 


92.50 


S€00 


a 


MAN'3MA 


,12 


Red 


.69 


2.00 


a 


MAN-4A6 


.27 


R«d 


1.95 


&.00 


L 


MAN'S 


,27 


Gr««n 


1.50 


4.00 


n 


MAN-6 


,6 


Red 


4,50 


12.00 


i: 


MAN-@4 


.4 


Red 


3.SO 


9.00 


n 


MAN-7 


,27 


Red 


l.OO 


2.50 


n 


MAN-S 


.27 


Yellow 


1,50 


4,0O 



ALL ABOV£ S¥ MOKSANTO 



Typ* 
SLA-1 

SLA-l 

SLA-1 

5LA-3 

SLA-3 

70T 

704A 

70ie 

FNO'TO 



C&ler 
Red 
Green 
Yell&w 
Green 
Yellow 
Red 
Red 
Red 
Red 



Sale 3 fof 
S1.95 $S.OO 
1,95 5.00 
1,9S S.OO 
4.95 12.0O 
12,00 
5,00 
5.0O 
3.00 
3.00 



SLA-l 



A — Commoa C^tbode, others Cotmnoii Anode 
B — With bubble ttmpiiiter 
C Plus or Minus 1 



Tab 
PRV 



Ainf» 

i*i»*t* 



po^^^ 



Units 



Set* 
$ .75 

.95 
1,25 
1.50 
1,99 

D *0O 115 
Q 600 ^^^ 



O^ 



LITRONIX ''JUMBO'S'' 

* single* %\z^t 1 N 3/4 X 5/18 

* Ouali eize: ,8 k ^9 x »29 

* 7-Se|fiffieflt, 25*rnlla per eefiment 



O too 

D 200 
Q 300 
□ 400 



Type 

O 7aiD 

B727E 
746F 
D 747 



Sdle 
$5.9S 
5.95 
3,95 
3,95 



3 for 
S15.00 
1S.OO 
ll.OO 
i 1 .DO 




'^^ Ter 



D — Plus or Minus 1 plus a digit (1 Vs digit!i> 

E — Pukldifcita 

F — Plus or Minus 1 



I 



[i 



□ MM5311 
n lMiil53l2 

□ MMS313 
n MIIIS314 
P fMIVl53l8 
P MM531G'A 



CLaCK CHIPS OM 
6-diBil 29 PUi 



i*f 



4-dlfflt 
6-diiclt 
6 -digit 

no «1erifi 



SS.50 

24-Piii ^-^J 

28-P1» S.50 

24-Pln 5-50 

40-Pin. •lerm 5,50 

3.95 



rm»f fidti pciMtJiite Rated; net i^O 
PKone Orders: Wakefield, Mn^a. (617) 246-.H-H2\^ 
Reiaih 16*18 Del Carmirtv St., Wakefield. Mass. 
^oiI Wttter Street^ C.O.D.'S MAY BE PHONED 

3 20c CATALOG Rber Optics, *ICs', Semrs. Pads 
MINJMUM OROER 54. OO 



WITH 0*TA SHCCTS 



BOX 9424 LVNIIFICLD.MASS. 01940 



readier service 



Check appropriate boxes for desired company 
brochures, data sheets or catalogs and mail ir» 
to 73, Include your zip code, please. Send 
money directly to advertisers, LIMIT: 25 
requests. 

ADVERTISER INDEX 



D 


Aldan El&c. 157 


n 


Kaufman Ind. 150 


a 


ApoUo 146 


n 


Kensco 21 


n 


A. P. Products 53 


D 


K -Enterprises 71 


n 


Antenna Mart 78 


D 


Kenwood 24 


■^■^ 


Atta& 149 


D 


Klaus %m 




*ATV 154 


D 


KLM 110 


a 


AiKJiolaftd 68 


Q 


Uvy 131 


Q 


Babylon 187 


O 


Mbgtmh 56 


a 


Bellatra 162 


P 


Mithna 188 189 


a 


Budwig 56 


a 


Midland 173 


o 


Buyers & Sailers 148 




•MITS 126 


D 


BYTE T66 


U 


MTech 152 


U 


C«Co 146 


D 


Newtronics Cll 


a 


CFP 78. 167 


D 


Non-Lmear Systems 20 


a 


01^99 39 


a 


Paiomar 118 


o 


Coakit 78 


D 


Poly PikS 191 


a 


Comm. Sptej^list* 109, ISO 


D 


Qu*fTi*nt 155 


a 


Comm. Specjjtlti&s 78 


Q 


Radio Am. Callbook 50 


u 


Cornel) 78 


n 


n»dio Stora 1S3 


o 


CR El eel tonics 152 


D 


RGS 175 


□ 


Curtis ISO 


o 


Rohn 161 


□ 


Davis tS4 


p 


S.D. Sales 176, 177 


a 


Dentron 52, 108 


cr 


Smith 174 


D 


DGM 150 


D 


Space 78 


a 


DuPage 186 


a 


Specialty Comm. 41 


a 


DXen Mag. 78 


a 


SpWtrum Co mm, 27 


a 


ECM 108 


a 


Standard Coinm. 79 


n 


Ehrhorn 57 


D 


Standard R^earch 155 


□ 


Eteetronic Develop. 154^ 157 


c 


Sumnar 135 


lJ 


Electronic Dirtrita. 165 


D 


Suntromx 182 183 


D 


ETCO 78 


a 


Talnar 72 


n 


Freck 108 


D 


Trt'Tek 124 


□ 


Gateway 140 


Q 


Trumbull 56 


"1 


GENAVE 104,105 


n 


Tucker 82-91 


n 


Godbout 1 84, 1 85 


p 


Ttifts 31.51,61,99, 120 


a 


Green Pub. 118 




145.151. 190 


o 


Ham Radio Center 1 72 


a 


TWSLabs 163 


D 


Hamtfonics 170 


□ 


Vanguard 168 


n 


HoBth 9 


a 


Vvgas Radii>171 


1. J 


Hertry 44 


D 


Venys Scientific 1 1 5 


G 


Hidcolc 8 


D 


VHP Eng. CIV 


1 


iCKits 130 


a 


WfriJ^nu 148 


D 


fCOM 119, 12S 


Q 


Wa»lco4ii 35 


n 


tnt, TAlecqmin 4, 5 


D 


Wilson 64. 65 


ij 


James 178, 179 


□ 


Windiammef 180, 181 


; 1 


Jan 102 


a 


World QSL 78 


n 


Jones, Mitrlin P. 104 


n 


¥««»u cm 



73 Stuff 
139, liS 160 



This 73 was acquired through: 

a NEWSSTAND n SUBSCRIPTION 

^Reader service Inquiries not solicitedp Corres- 
pond directly to company. 



Reader's Service 



AUGUST 1975 



73 Inc, Peterborough fSIH 03458 
Please print or type. 

Name 



Call 



Address 



City 



State 



Coupon expires in 60 days , 



PROPAGATION CHART 

J.H, Nelson 

Good (open) Poor (0) 

Fair(n) 



August 



- 1975 



Smm 



Mon 



ue 



m^ Tii 



Fri 



Sai 



H 




3 



10 



4 
II 







24 




® 25 



5 

26 



6 r? 



'3 





9 




1 




20 




21 




22 




33 


27 




28 




29 




30 



EASTERN UNITED STATES TO: 1 


GhTT: E» 03 0« 00 Ot 


10 


1Z 14 1« tt » 22 


ALASKA 


7A 


7A 


7 


7 


7 




7 


1 
7 


7 


7 


7A 


7A 


ARGENTINA 


14 


14 


7 


7 


7 




7A 


14 


14 


14 


14A 


14A 


AUSTRALIA 


14 


34 


7B 


7B 


7 




7 


7 


7 


7 


14 


14 


CANAL ZONE 


14 


7A 


7 


7 


1 




7A 


14 


!4 


W 


14 


14 


ENGLAND 


T 


7 


7 


7 


7 




7A 


14 


14 


14 


H 


14 


HAWAII 


14 


14 


7B 


7 


7 




? 


7 


7A 


-14 , 


?1 


^* 


tNDJA 


T 


7 


7 


i 


7p 




7 


7 


7A 


14 


7A 


T 


JAFAM 


14 


7A 


7 


7 


7 




7 


7 


7 


f 


7 


14 


MEXICO 


14 


7A 


7 


7 


7 




7 


7A 


14 


14 


'^ 


14 


9m\^\P9\H^^ 


14 


?A 


7E 


l^ 


7^ 


70 


^ 


7 


1 7 


, T* 


14 1 


PUCiiTO nico 


7A 


1 


1 


7 


7 




7 


7 


7A 


14 


14 


14 


SOUTH AFRICA 


7 


J 


3A 


7 


7B 


\4 


14 


14 


14 


14 


14 


7 


U £. S. R. 


1 


7 


7 


7 


7 




14 


14 


14 


14 


14 


7 


WEST COAST 


14 


14 


7 


7 


7 


- 


7 


7A 


14 


14 


14 


14 


CENTRAL UNITEl 


> 


STATES TO: 


ALASPCA 


14 


T4 


7 






7 






7 ! 7 


? 




ARGENTINA 


t4 


14 


7A 






7 




14 


14 


14 


14 


)4A 


AtlSTRAilA 


14 


U 


7A 


70 




7 






7 


7 


14 




CAftlAL ZCM^ 


t4 


t4 


J 






7 




14 


14 


14 


14 




ENGLAND 


7 


7 


7 






7 






7A 


7A 


14 




. HAWAh 


T4 


14 


14 






7 






14 


14 


14 




INDtA 


7A 


7A 


7 






7 






7A 


7A 


7 




JAPAN 


14 


\4 


7A 






7 






7 


7 


1 ^ 




MEXICO 


14 


7 


7 




3A 


3A 






7 


7 


14 




^ILIPPINES 


14 


14 


7B 


ra 


7ft 


7B 






7 


7 


TA 




puEfrro Bicp 


1* 


7A 


7 






7 




14 


14 


14 


14 




SOUTH AFRICA 


7 


? 


3A 




Tft 


7B 


14 


14 


14 


14 


14 




U.S.S,ft, 


7 


7 


T 






7 






7A 


14 


14 





















WESTERN UNITED STATES TO: 



ALASKA 



ARGENTINA 



AUSTRALIA 



CANAL ZONE 



7A 



14 



14 



14 



ENGLAND 



HAWAII 



tNDfA 



JAPAN 



M£XIC0 



PHILIPPINES 



PUERTO RICO 



SOUTH AFRICA 



ass, ft. 



EAST COAST 



14 



T4 



14 



14 



14 



14 



?A 



14 



14A 



14 



14A 



14 



14 



14 



14 



14 



14 



7A 



7A 



T4 



14 



14 



14 



14 



3A 



14 



14 



7A 



7B 



7 



7fl 



7a 



7B 



7B 



7B 



7B 



—L 



14 



7A 



7A 



14 



M 



14 



14 



7A 



14 



14 



14 



7A 



14 



14 



7B 



7A 



14 



14 



14 



J3^ 



14 



14 



14 



14 



1* H 



14A 



14 



14 



14 



r* 



%* 



7A 



14 



14 



!4 



14 



14 



14 



14 



14 



14 



14 



14 



14 



A = Next higher frequency may be useful also* 
= Difficult circuit this period. 



192 



• /x. %^^ 



73 MAGAZtNE 




YAESUFT-101E TRANSCEIVER 




Now, more radio 



from the 
radio company. 



Are Yaesu's FT-101 's the finest all- 
around transceivers in the world? 
Yes — and now the best is even 
better. The new FT-101 E includes 
a potent R. F. speech processor. Plus 
improved, easy-to-use lever switches. 
A more refined clarifier control 
for push-button, independent 
clarifier operation. There's also a 
1 60 meter crystal included without 
extra charge. 

And all the other features that 
have made the FT-1 01 series of tran- 
sceivers among the world's most 
popular are still here; 260 watts SSB 



PEP. Globe-circling power on CW 
and AM. 160 to 10 meters range. 
0.3uV receiving sensitivity. And 
one very important feature you never 
want to forget is the famous Yaesu 
warranty, strong dealer network and 
convenient serviceability. 

If you're a serious amateur, 
you're always looking for more radio. 
And the FT-101 E is just that. $749* 
buys you a million bucks worth of 
enjoyment. See your Yaesu dealer 
or write for our catalog. Yaesu 
Musen USA, Inc. 7625 E. Rosecrans, 
No, 29. Paramount, Calif. 90723. 



VAg 




U 



The radlom 



♦FT-101 EE {less 
processor): $659. 



mm 



I 




Problem 



Solutidn 



Your local club has decided to put up a repeater, but 
funds are limited and you know that an old commercial 
tube rig converted will work but never will be first rate. 

"The Life Saver" — A state of the art completely solid 
state repeater. Complete including CW-ID, control cir- 
cuitry, power supply (12V 12Amp) and all hardware. 
Packaged to take up to 25,000 microvolts before desensing. 



Kit 



$364.95 



PRICES 

Factory wired and tested 



$595.00 



Need Cavaties? With kit or wired and tested repeater, add $399.95 for 

commercial grade 6 cavity system. 



I 



hf engineering 

120 WATER ST. • PO SOX 1921 • 8INGHAMT0N, NY 13902 • 607723-9574 

Dt\^fSiON or BMOWNiAN £L£CTfiONtCS CORt^. 



masii^r charge 



-TI"4**-